Direct catalytic conversion of ethanol to hydrocarbon blend-stock can increase biofuels use in current vehicles beyond the ethanol blend-wall of 10-15%. Literature reports describe quantitative conversion of ethanol over zeolite catalysts but high C2 hydrocarbon formation renders this approach unsuitable for commercialization. Furthermore, the prior mechanistic studies suggested that ethanol conversion involves endothermic dehydration step. Here, we report the complete conversion of ethanol to hydrocarbons over InV-ZSM-5 without added hydrogen and which produces lower C2 (products come from the hydrocarbon pool type mechanism and dehydration step is not necessary. Thus, our method of direct conversion of ethanol offers a pathway to produce suitable hydrocarbon blend-stock that may be blended at a refinery to produce fuels such as gasoline, diesel, JP-8, and jet fuel, or produce commodity chemicals such as BTX.

Full Text Available Methane conversion to higher hydrocarbons by pulsed glow discharge at the atmospheric pressure was investigated. The energy efficiency up to 10 % was obtained which is higher than any value ever published for nonequilibrium plasma conversion of pure methame. This method has a potential for development and it is expected that the energy efficiency will be improved further if the plasma parameters are optimized.

This patent describes a process for hydrocracking hydrocarbon oils into products of lower average molecular weight and lower average boiling point. It comprises contacting a hydrocarbon oil at a temperature between 250{sup 0}C and 500{sup 0}C and a pressure up to 300 bar in the presence of hydrogen with a catalyst consisting essentially of a Y zeolite modified to have a unit cell size below 24.35A, a water absorption capacity (at 25{sup 0}C and a rho/rho/sub o/ value of 0.2) of at least 8% by weight of the zeolite and a pore volume of at least 0.25 ml/g wherein between 10% and 60% of the total pore volume is made up of pores having a diameter of at least 8 nm; an alumina binder and at least one hydrogenation component selected from the group consisting of a Group VI metal, a Group VIII metal and mixtures thereof.

A reactor for reactive co-conversion of heavy hydrocarbons and hydrocarbon gases and includes a dielectric barrier discharge plasma cell having a pair of electrodes separated by a dielectric material and passageway therebetween. An inlet is provided for feeding heavy hydrocarbons and other reactive materials to the passageway of the discharge plasma cell, and an outlet is provided for discharging reaction products from the reactor. A packed bed catalyst may optionally be used in the reactor to increase efficiency of conversion. The reactor can be modified to allow use of a variety of light sources for providing ultraviolet light within the discharge plasma cell. Methods for upgrading heavy hydrocarbons are also disclosed.

The installation for vapor conversion of hydrocarbons (Uv) with the formation of a mixture of H2 and C02 is a catalyst chamber (KK) filled with longitudinally disposed thin pipes (with thin walls) or with pipe units made of dolomite, MgO or potassium aluminate. These pipes have a multilayered coating (Pk) on their internal and external surfaces (Pv), which contain catalytically active components. Such pipes or pipe units form a honeycombed structure with through longitudinal channels. The catalyst chamber itself is made of a ceramic material and has a heating winding outside for heating the catalyst. To save fuel and to increase the efficiency (KPD) of the heating device, the catalyst chamber is in turn enclosed by two additional shells filled with heat conducting packings which are easily penetrated by the gases being processed. The hydrocarbon vapors or gaseous fuel from the natural gas or methane and the steam are fed through the above cited heat exchange layers with packings into the facial part of the catalytic chamber, in which the conversion of the hydrocarbons occurs with the production of H2 and C02. From the catalyzer layer the mixture of gases and steam goes through a refrigerator into a trap for the steam excess and when it is necessary, into a C02 absorber and then, pure H2 is discharged from the latter. Such a catalytic installation is convenient to use for producing pure H2 from natural gas, methane, propane or kerosene.

With fossil fuels still predicted to contribute close to 80 % of the primary energy consumption by 2040, methods to limit further CO2 emissions in the atmosphere are urgently needed to avoid the catastrophic scenarios associated with global warming. In parallel with improvements in energy efficiency and CO2 storage, the conversion of CO2 has emerged as a complementary route with significant potential. In this work we present the direct thermo-catalytic conversion of CO2 to hydrocarbons using a novel iron nanoparticle-carbon nanotube (Fe@CNT) catalyst. We adopted a holistic and systematic approach to CO2 conversion by integrating process optimization-identifying reaction conditions to maximize conversion and selectivity towards long chain hydrocarbons and/or short olefins-with catalyst optimization through the addition of promoters. The result is the production of valuable hydrocarbons in a manner that can approach carbon neutrality under realistic industrial process conditions.

This patent describes a process for hydrocracking hydrocarbon oils into products of lower average molecular weight and lower average boiling point. It comprises contacting hydrocarbon oil at a temperature between 250{sup 0}C and 500{sup 0}C and a pressure up to 300 bar in the presence of hydrogen with a catalyst consisting essentially of a Y zeolite modified to have a unit cell size below 24.40 A, a water adsorption capacity (at 25{sup 0}C and a rho/rho/sub o/ value of 0.2) of between 10% and 15% by weight of the zeolite and a pore volume of at least 0.25 ml/g wherein between 10% and 60% of the total pore volume is made up of pores having a diameter of at least 8 nm; am amorphous cracking component, a binder and at least one hydrogenation component selected from the group consisting of a Group VI metal, a Group VIII metal and mixtures thereof.

The present invention is directed to the one step selective conversion of starch, cellulose, or glucose to molecules containing 7 to 26 contiguous carbon atoms. The invention is also directed to the conversion of those intermediates to saturated hydrocarbons. Such saturated hydrocarbons are useful as, for example, fuels.

The infrared emission spectra of methane, H', CH and C2 hydrocarbons in natural gas were measured. The process of methane decomposition and C2 hydrocarbons formation was investigated. The experiment showed that the time and conditions of methane decomposition and C2 hydrocarbons formation were different. Methane conversion rate increased with the increase in the current and decrease in the amount of methane. Furthermore, an examination of the reaction mechanisms revealed that free radicals played an important role in the chain reaction.

Embodiments of the present invention are directed to the conversion of a source material (e.g., a depolymerized oligosaccharide mixture, a monomeric sugar, a hydrolysate, or a mixture of monomeric sugars) to intermediate molecules containing 7 to 26 contiguous carbon atoms. These intermediates may also be converted to saturated hydrocarbons. Such saturated hydrocarbons are useful as, for example, fuels.

This technology pathway case investigates the biological conversion of biomass-derived sugars to hydrocarbon biofuels, utilizing data from recent literature references and information consistent with recent pilot-scale demonstrations at NREL. Technical barriers and key research needs have been identified that should be pursued for the pathway to become competitive with petroleum-derived gasoline-, diesel-, and jet-range hydrocarbon blendstocks.

A method of converting organic solids to liquid and gaseous hydrocarbons includes impregnating an organic solid with photosensitizing ions and exposing the impregnated solid to light in a non-oxidizing atmosphere for a time sufficient to photocatalytically reduce the solid to at least one of a liquid and a gaseous hydrocarbon.

A method for converting an alcohol to a hydrocarbon, the method comprising contacting said alcohol with a metal-loaded zeolite catalyst at a temperature of at least 100.degree. C. and up to 550.degree. C., wherein said alcohol can be produced by a fermentation process, said metal is a positively-charged metal ion, and said metal-loaded zeolite catalyst is catalytically active for converting said alcohol to said hydrocarbon.

This is the Final Report of the five-year project Using Ionic Liquids in Selective HydrocarbonConversion Processes (DE-FC36-04GO14276, July 1, 2004- June 30, 2009), in which we present our major accomplishments with detailed descriptions of our experimental and theoretical efforts. Upon the successful conduction of this project, we have followed our proposed breakdown work structure completing most of the technical tasks. Finally, we have developed and demonstrated several optimized homogenously catalytic methane conversion systems involving applications of novel ionic liquids, which present much more superior performance than the Catalytica system (the best-to-date system) in terms of three times higher reaction rates and longer catalysts lifetime and much stronger resistance to water deactivation. We have developed in-depth mechanistic understandings on the complicated chemistry involved in homogenously catalytic methane oxidation as well as developed the unique yet effective experimental protocols (reactors, analytical tools and screening methodologies) for achieving a highly efficient yet economically feasible and environmentally friendly catalytic methane conversion system. The most important findings have been published, patented as well as reported to DOE in this Final Report and our 20 Quarterly Reports.

Amoco oil Company, has investigated the direct, non-catalytic conversion of light hydrocarbon gases to liquid fuels (particularly methanol) via partial oxidation. The primary hydrocarbon feed used in these studies was natural gas. This report describes work completed in the course of our two-year project. In general we determined that the methanol yields delivered by this system were not high enough to make it economically attractive. Process variables studied included hydrocarbon feed composition, oxygen concentration, temperature and pressure effects, residence time, reactor design, and reactor recycle.

Amoco oil Company, has investigated the direct, non-catalytic conversion of light hydrocarbon gases to liquid fuels (particularly methanol) via partial oxidation. The primary hydrocarbon feed used in these studies was natural gas. This report describes work completed in the course of our two-year project. In general we determined that the methanol yields delivered by this system were not high enough to make it economically attractive. Process variables studied included hydrocarbon feed composition, oxygen concentration, temperature and pressure effects, residence time, reactor design, and reactor recycle.

Recently, a number of papers about direct oxidation of methane and hydrocarbon in solid oxide fuel cells (SOFC) at relatively low temperatures (about 700degreesC) have been published. Even though the conversion of almost dry CH4 at 1000degreesC on ceramic anodes was demonstrated more than 10 years...

In support of the Bioenergy Technologies Office, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) are undertaking studies of biomass conversion technologies to identify barriers and target research toward reducing conversion costs. Process designs and preliminary economic estimates for each of these pathway cases were developed using rigorous modeling tools (Aspen Plus and Chemcad). These analyses incorporated the best information available at the time of development, including data from recent pilot and bench-scale demonstrations, collaborative industrial and academic partners, and published literature and patents. This technology pathway case investigates the biological conversion of biomass derived sugars to hydrocarbon biofuels, utilizing data from recent literature references and information consistent with recent pilot scale demonstrations at NREL. Technical barriers and key research needs have been identified that should be pursued for the pathway to become competitive with petroleum-derived gasoline, diesel and jet range hydrocarbon blendstocks.

The ability to convert renewable biomass into fuels and chemicals is one of the most important steps on our path to green technology and sustainable development. However, the complex composition of biomass poses a major problem for established conversion technologies. The high temperature of thermochemical biomass conversion often leads to the appearance of undesirable byproducts and waste. The catalytic conversion has reduced yield and feedstock range. Plasma-catalytic reforming technology opens a new path for biomass conversion by replacing feedstock-specific catalysts with free radicals generated in the plasma. We studied the plasma-catalytic conversion of several renewable hydrocarbons using the air plasma created by rotating gliding discharge. We found that plasma-catalytic hydrocarbonconversion can be conducted at significantly lower temperatures (500 K) than during the thermochemical ( 1000 K) and catalytic (800 K) conversion. By using gas chromatography, we determined conversion products and found that conversionefficiency of plasma-catalytic conversion reaches over 85%. We used obtained data to determine the energy yield of hydrogen in case of plasma-catalytic reforming of ethanol and compared it with other plasma-based hydrogen-generating systems.

With chlorinated solvents unlikely to be permitted for use in solution-processed organic solar cells in industry, there must be a focus on developing nonchlorinated solvent systems. Here we report high-efficiency devices utilizing a low-bandgap donor polymer (PffBT4T-2DT) and a nonfullerene acceptor (EH-IDTBR) from hydrocarbon solvents and without using additives. When mesitylene was used as the solvent, rather than chlorobenzene, an improved power conversionefficiency (11.1%) was achieved without the need for pre- or post-treatments. Despite altering the processing conditions to environmentally friendly solvents and room-temperature coating, grazing incident X-ray measurements confirmed that active layers processed from hydrocarbon solvents retained the robust nanomorphology obtained with hot-processed chlorinated solvents. The main advantages of hydrocarbon solvent-processed devices, besides the improved efficiencies, were the reproducibility and storage lifetime of devices. Mesitylene devices showed better reproducibility and shelf life up to 4000 h with PCE dropping by only 8% of its initial value.

In this paper the effect of catalyst and carrier in electric field enhanced plasma on methane conversion into C2 hydrocarbons was investigated. Methane coupling reaction was studied in the system of continuous flow reactor on Ni, MoO3, MnO2 catalysts and different ZSM-5 carriers. The per pass conversion of methane can be as high as 22%, the selectivity of ethylene can be as high as 23.8%, of acetylene 60.8%, of ethane 5.4% and of total C2 hydrocarbons was more than 90%. ZSM-5-25 was the better carrier and MnO2 was the better active component. The efficiency of energy was as high as 7.81%.

The synthesis of hydrocarbon fuels directly from synthesis gas (i.e. one step process) was investigated with a catalytic system comprised of HZSM-5 physically mixed with either a methanol synthesis catalyst or a higher alcohols synthesis (HAS) catalyst. The metal sites of the methanol or HAS synthesis catalyst enable the conversion of syngas to alcohols, whereas HZSM-5 provides acid sites required for methanol dehydration, and dimethyl ether-to-hydrocarbons reactions. Catalytic performance for HZSM-5 when mixed with either a 5 wt.% Pd/ZnO/Al2O3 methanol synthesis catalyst or a HAS catalyst was evaluated at 300°C, 70 bars, GHSV=700 h-1 and H2/CO=1 using a HZSM-5: alcohols synthesis catalyst weight ratio of 3:1. The major difference observed between the methanol synthesis and HAS catalyst mixtures was found in the production of durene which is an undesirable byproduct. While durene formation is negligible with any of the HAS catalysts mixed with the HZSM-5 evaluated in this study, it represents almost 50% of the C5+ fraction for the methanol synthesis catalyst (5 wt.% Pd/ZnO/Al2O3 ) mixed with HZSM-5. This presents an advantage for using HAS catalysts over the methanol synthesis catalyst to minimize the durene by-product. The yield toward the desired C5+ hydrocarbons is thus twice higher with selected HAS catalysts as compared to when HZSM-5 is mixed with 5 wt.% Pd/ZnO/Al2O3. Among all the HAS catalysts evaluated in this study, a catalyst with 0.5 wt.% Pd/FeCoCu catalyst was found the most promising due to higher production of C5+ hydrocarbons and low durene formation. The efficiency of the one-step process was thus further evaluated using the HZSM-5: 0.5 wt.% Pd/FeCoCu catalyst mixture under a number of process conditions to maximize liquid hydrocarbons product yield. At 300oC, 70 bars, GHSV = 700 h-1 and HZSM-5: 0.5 wt.% Pd/FeCoCu = 3:1 (wt.), the C5+ fraction represents 48.5% of the hydrocarbons. Unfortunately, it is more difficult to achieve higher selectivity

Natural gas is widely abundant, is easily withdrawn from reservoirs, is commonly produced as an associated gas along with crude oil production, and is found in many geologic settings as a resource separate from oil. A much larger fraction of the natural gas may be produced from a gas reservoir, as compared with a crude oil reservoir. However, natural gas is normally transported by pipeline, and the energy throughput of such a pipeline is perhaps only 20% to 30% of the throughput of an oil pipeline of the same size and cost. Gas is difficult to transport in moderate quantities at low cost, as it must either have a special pipeline or must be liquified into LNG, shipped in cryogenic LNG tankers, and regasified chemical stability of methane has made it difficult to convert it directly into conventional hydrocarbon fuel mixtures, and has also impeded its use as a feedstock for petrochemical production. Experiments are described in which a methane plasma is created, and the resulting methyl and hydrogen ions have been accelerated within a microchannel array so that they interact with neutral methane molecules on the inside surfaces of the microchannels. No catalysts are used, and the device operates at room temperature. Impact energies of the ions are in the range of 15 ev to greater than 100 ev, and the energy delivered in the interaction at the surfaces has caused the production of larger hydrocarbon molecules, such as C{sub 2}H{sub 2}, C{sub 2}H{sub 4}, and C{sub 2}H{sub 6}, along with C{sub 3}, C{sub 4}, C{sub 5}, C{sub 6}, C{sub 7}, and C{sub 8} molecules. Conversion effectiveness is greater at higher pressure, due to the increased ionic activity. The costs of production of the plasma conversion devices are projected to be quite low, and the technology appears to be commercially and economically feasible.

Frequency conversion process is studied in a medium of atoms with a $\\Lambda$ configuration of levels, where transition between two lower states is driven by a microwave field. In this system, conversionefficiency can be very high by virtue of the effect of electromagnetically induced transparency (EIT). Depending on intensity of the microwave field, two regimes of EIT are realized: ''dark-state'' EIT for the weak field, and Autler-Townes-type EIT for the strong one. We study both cases via analytical and numerical solution and find optimum conditions for the conversion.

Atmospheric pressure, non-thermal plasma-activated-catalysis is showing real promise in a number of applications. Here we report on how electrical, visible and FTIR spectroscopy and mass spectroscopy measurements in a kHz atmospheric pressure He plasma jet coupled with a Ag/Al2O3 catalyst allowed us produce and confirm a strong enhancement of both NOx and hydrocarbonconversion at a measured gas temperature of <= 250° C. How these and other measurements have provided an insight into the fundamental physical and chemical processes in the plasma environment that have helped us move to a more efficient system and other processes will be discussed.

In view of impending depletion of hydrocarbon fuel resources and their negative environmental impact, it is imperative to significantly increase the energy conversionefficiency of hydrocarbon-based power generation systems. The combination of a hydrocarbon decomposition reactor with a direct carbon and hydrogen fuel cells (FC) as a means for a significant increase in chemical-to-electrical energy conversionefficiency is discussed in this paper. The data on development and operation of a thermocatalytic hydrocarbon decomposition reactor and its coupling with a proton exchange membrane FC are presented. The analysis of the integrated power generating system including a hydrocarbon decomposition reactor, direct carbon and hydrogen FC using natural gas and propane as fuels is conducted. It was estimated that overall chemical-to-electrical energy conversionefficiency of the integrated system varied in the range of 49.4-82.5%, depending on the type of fuel and FC used, and CO{sub 2} emission per kW{sub el}h produced is less than half of that from conventional power generation sources. (author)

A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

The experiments are carried out in the system of continuous flow reactors with dielectric-barrier discharge (DBD) for studies on the conversion of natural gas to C2 hydrocarbons through plasma catalysis under the atmosphere pressure and room temperature. The influence of discharge frequency, structure of electrode, discharge voltage, number of electrode, ratio of H2/CH4, flow rate and catalyst on conversion of methane and selectivity of C2 hydrocarbons are investigated. At the same time, the reaction process is investigated. Higher conversion of methane and selectivity of C2 hydrocarbons are achieved and deposited carbons are eliminated by proper choice of parameters. The appropriate operation parameters in dielectric-barrier discharge plasma field are that the supply voltage is 20-40 kV (8.4-40 W), the frequency of power supply is 20 kHz, the structure of (b) electrode is suitable, and the flow of methane is 20-60 mL@min?1. The conversion of methane can reach 45%, the selectivity of C2 hydrocarbons is 76%, and the total selectivity of C2 hydrocarbons and C3 hydrocarbons is nearly 100%. The conversion of methane increases with the increase of voltage and decreases with the flow of methane increase; the selectivity of C2 hydrocarbons decreases with the increase of voltage and increases with the flow of methane increase. The selectivity of C2 hydrocarbons is improved with catalyst for conversion of natural gas to C2 hydrocarbons in plasma field. Methane molecule collision with radicals is mainly responsible for product formation.

Thermal protection of heat-stressed surfaces of a high-speed vehicle flying in dense layers of atmosphere is one of the topical issues. Not of a less importance is also the problem of hydrocarbon fuel combustion in a supersonic air flow. In the concept under development, it is supposed that in the most high-stressed parts of airframe and engine, catalytic thermochemical reactors will be installed, wherein highly endothermic processes of steam conversion of hydrocarbon fuel take place. Simultaneously with heat absorption, hydrogen generation will occur in the reactors. This paper presents the results of a study of conversion of hydrocarbon fuel in a slit reactor.

Novel reactor configurations featuring catalysts supported on monolithic or honeycomb structures are being increasingly used for a number of applications. In this work, a zeolite-coated monolithic reactor is employed for the conversion of methanol to gasoline-range hydrocarbons. Experimental results show that the conversion and hydrocarbon product distribution compare favorably with data reported for fixed and fluid beds. Mathematical modeling shows that the conversion here is controlled by diffusion in the molecule-sized intracrystalline pores of the zeolite structure. This finding is of considerable important because it demonstrates that monolithic reactors are well-suited to zeolite-based catalytic processes.

The successful production of higher hydrocarbons from methane depends on the stability or the oxidation rate of the intermediate products. The performances of the BZSM-5 and the modified BZSM-5 catalysts were tested for ethylene conversion into higher hydrocarbons. The catalytic experiments were carried out in a fixed-bed micro reactor at atmospheric pressure. The catalysts were characterized using XRD, NH3-TPD, and IR for their structure and acidity. The result suggests that BZSM-5 is a weak acid. The introduction of copper into BZSM-5 improved the acidity of BZSM-5. The conversion of ethylene toward higher hydrocarbons is dependent on the acidity of the catalyst. Only weaker acid site is required to convert ethylene to higher hydrocarbons. The loading of Cu on BZSM-5 improved the selectivity for higher hydrocarbons especially at low percentage. The reactivity of ethylene is dependent on the amount of acidity as well as the presence of metal on the catalyst surface. Cu1%BZSM-5 is capable of converting ethylene to higher hydrocarbons. The balances between the metal and acid sites influence the performance of ethylene conversion and higher hydrocarbon selectivity. Higher loading of Cu leads to the formation of COx.

Single photons are excellent quantum information carriers: they were used in the earliest demonstrations of entanglement and in the production of the highest-quality entanglement reported so far. However, current schemes for preparing, processing and measuring them are inefficient. For example, down-conversion provides heralded, but randomly timed, single photons, and linear optics gates are inherently probabilistic. Here we introduce a deterministic process--coherent photon conversion (CPC)--that provides a new way to generate and process complex, multiquanta states for photonic quantum information applications. The technique uses classically pumped nonlinearities to induce coherent oscillations between orthogonal states of multiple quantum excitations. One example of CPC, based on a pumped four-wave-mixing interaction, is shown to yield a single, versatile process that provides a full set of photonic quantum processing tools. This set satisfies the DiVincenzo criteria for a scalable quantum computing architecture, including deterministic multiqubit entanglement gates (based on a novel form of photon-photon interaction), high-quality heralded single- and multiphoton states free from higher-order imperfections, and robust, high-efficiency detection. It can also be used to produce heralded multiphoton entanglement, create optically switchable quantum circuits and implement an improved form of down-conversion with reduced higher-order effects. Such tools are valuable building blocks for many quantum-enabled technologies. Finally, using photonic crystal fibres we experimentally demonstrate quantum correlations arising from a four-colour nonlinear process suitable for CPC and use these measurements to study the feasibility of reaching the deterministic regime with current technology. Our scheme, which is based on interacting bosonic fields, is not restricted to optical systems but could also be implemented in optomechanical, electromechanical and superconducting

The ability to control nanoscale features precisely is increasingly being exploited to develop and improve monofunctional catalysts(1-4). Striking effects might also be expected in the case of bifunctional catalysts, which are important in the hydrocracking of fossil and renewable hydrocarbon source

An efficient ammonia terahertz(THz)cavity laser is reported experimentally.Unlike the past design schemes such as hole couplers and freestanding mesh couplers,in our systems the input and output couplers are fabricated by depositing nickel capacitive metallic meshes on ZnSe and high-resistivity silicon substrates.Thus the couplers not only can be constructed as an F-P oscillator but also can be used as sealed windows that are easier to perform the adjustment of alignment with.To enhance THz laser output energy and photon conversionefficiency,the dominant factors such as pump intensity and gas pressure are investigated experimentally.Finally,a 1.35 mJ terahertz radiation of ammonia laser with 90μm wavelength(3.33THz)operating at 1.09kPa pumped by a 402mJ TEA CO_2 laser with 9R(16)line is generated,and photon conversionefficiencies of 6.5% are achieved.

Direct conversion of methane to C2 hydrocarbons via cold plasma reaction with catalysts has been studied at room temperature and atmospheric pressure. Methane can be converted into C2 hydrocarbons in different selectivity depending on the form of the reactor, power of plasma, flow rate of methane, ratio of N2/CH4 and nature of the catalysts. The selectivity to C2 hydrocarbons can reach as high as 98.64%, and the conversion of methane as high as 60% and the yield of C2 hydrocarbons as high as 50% are obtained. Coking can be minimized under the conditions of: proper selection of the catalysts,appropriate high flow rate of inlet methane and suitable ratio of N2 to CH4. The catalyst surface provides active sites for radical recombination.

Catalysts for converting methane to higher hydrocarbons such as ethane and ethylene in the presence of oxygen at temperatures in the range of about 700.degree. to 900.degree. C. are described. These catalysts comprise calcium oxide or gadolinium oxide respectively promoted with about 0.025-0.4 mole and about 0.1-0.7 mole sodium pyrophosphate. A preferred reaction temperature in a range of about 800.degree. to 850.degree. C. with a preferred oxygen-to-methane ratio of about 2:1 provides an essentially constant C.sub.2 hydrocarbon yield in the range of about 12 to 19 percent over a period of time greater than about 20 hours.

Full Text Available As a potential source of biofuel, the green colonial microalga Botryococcus braunii produces large amounts of hydrocarbons that are accumulated in the extracellular matrix. Generally, pretreatment such as drying or heating of wet algae is needed for sufficient recoveries of hydrocarbons from B. braunii using organic solvents. In this study, the Showa strain of B. braunii was cultured in media derived from the modified Chu13 medium by supplying artificial seawater, natural seawater, or NaCl. After a certain period of culture in the media with an osmotic pressure corresponding to 1/4-seawater, hydrocarbon recovery rates exceeding 90% were obtained by simply mixing intact wet algae with n-hexane without any pretreatments and the results using the present culture conditions indicate the potential for hydrocarbon milking.Seawater was used for efficienthydrocarbon extraction from Botryococcus braunii. The alga was cultured in media prepared with seawater or NaCl. Hydrocarbon recovery rate exceeding 90% was obtained without any pretreatment.

Amoco oil Company, has investigated the direct, non-catalytic conversion of light hydrocarbon gases to liquid fuels (particularly methanol) via partial oxidation. The primary hydrocarbon feed used in these studies was natural gas. This report describes work completed in the course of our two-year project. In general we determined that the methanol yields delivered by this system were not high enough to make it economically attractive. Process variables studied included hydrocarbon feed composition, oxygen concentration, temperature and pressure effects, residence time, reactor design, and reactor recycle.

Amoco oil Company, has investigated the direct, non-catalytic conversion of light hydrocarbon gases to liquid fuels (particularly methanol) via partial oxidation. The primary hydrocarbon feed used in these studies was natural gas. This report describes work completed in the course of our two-year project. In general we determined that the methanol yields delivered by this system were not high enough to make it economically attractive. Process variables studied included hydrocarbon feed composition, oxygen concentration, temperature and pressure effects, residence time, reactor design, and reactor recycle.

We have measured photoionization-efficiency curves for pyrene, fluoranthene, chrysene, perylene, and coronene in the photon energy range of 7.5-10.2 eV and derived their photoionization cross-section curves in this energy range. All measurements were performed using tunable vacuum ultraviolet (VUV) radiation generated at the Advanced Light Source synchrotron at Lawrence Berkeley National Laboratory. The VUV radiation was used for photoionization, and detection was performed using a time-of-flight mass spectrometer. We measured the photoionization efficiency of 2,5-dimethylfuran simultaneously with those of pyrene, fluoranthene, chrysene, perylene, and coronene to obtain references of the photon flux during each measurement from the known photoionization cross-section curve of 2,5-dimethylfuran.

The experiments are carried out in the system of continuous flow reactors with dielectric-barrier discharge (DBD) for studies on the conversion of natural gas to C2 hydrocarbons through plasma catalysis under the atmosphere pressure and room temperature. The influence of discharge frequency, structure of electrode, discharge voltage, number of electrode, ratio of H2/CH4, flow rate and catalyst on conversion of methane and selectivity of C2 hydrocarbons are investigated. At the same time, the reaction process is investigated. Higher conversion of methane and selectivity of C2 hydrocarbons are achieved and deposited carbons are eliminated by proper choice of parameters. The appropriate operation parameters in dielectric-barrier discharge plasma field are that the supply voltage is 20-40 kV (8.4-40 W), the frequency of power supply is 20 kHz, the structure of (b) electrode is suitable, and the flow of methane is 20-60 ml · min-1. The conversion of methane can reach 45%, the selectivity of C2 hydrocarbons i

In recent years, the theory of cooperation and conversational implicature, along with the theory of face, the principles of politeness and the theory of relevance, has been paid much attention in language teaching. From cognitive angle, all these theories

In addition to inorganic catalysts that react with methane, it is well-known that a select group of aerobic soil/water bacteria called methanotrophs can efficiently and selectively utilize methane as the sole source of their energy and carbon for cellular growth. The first reaction in this metabolic pathway is catalyzed by the enzyme methane monooxygenase (MMO) forming methanol. Methanol is a technology important product from this partial oxidation of methane since it can be easily converted to liquid hydrocarbon transportation fuels (gasoline), used directly as a liquid fuel or fuel additive itself, or serve as a feedstock for chemicals production. This naturally occurring biocatalyst (MMO) is accomplishing a technologically important transformation (methane directly to methanol) for which there is currently no analogous chemical (non-biological) process. The authors approach has been to use the biocatalyst, MMO, as the initial focus in the development of discrete chemical catalysts (biomimetic complexes) for methane conversion. The advantage of this approach is that it exploits a biocatalytic system already performing a desired transformation of methane. In addition, this approach generated needed new experimental information on catalyst structure and function in order to develop new catalysts rationally and systematically. The first task is a comparative mechanistic, biochemical, and spectroscopic investigation of MMO enzyme systems. This work was directed at developing a description of the structure and function of the catalytically active sites in sufficient detail to generate a biomimetic material. The second task involves the synthesis, characterization, and chemical reactions of discrete complexes that mimic the enzymatic active site. These complexes were synthesized based on their best current understanding of the MMO active site structure.

The U.S. Department of Energy promotes the production of a range of liquid fuels and fuel blendstocks from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass collection, conversion, and sustainability. As part of its involvement in this program, the Idaho National Laboratory (INL) investigates the feedstock logistics economics and sustainability of these fuels. Between 2000 and 2012, INL conducted a campaign to quantify the economics and sustainability of moving biomass from standing in the field or stand to the throat of the biomass conversion process. The goal of this program was to establish the current costs based on conventional equipment and processes, design improvements to the current system, and to mark annual improvements based on higher efficiencies or better designs. The 2012 programmatic target was to demonstrate a delivered biomass logistics cost of $35/dry ton. This goal was successfully achieved in 2012 by implementing field and process demonstration unit-scale data from harvest, collection, storage, preprocessing, handling, and transportation operations into INL’s biomass logistics model. Looking forward to 2017, the programmatic target is to supply biomass to the conversion facilities at a total cost of $80/dry ton and on specification with in-feed requirements. The goal of the 2017 Design Case is to enable expansion of biofuels production beyond highly productive resource areas by breaking the reliance of cost-competitive biofuel production on a single, abundant, low-cost feedstock. If this goal is not achieved, biofuel plants are destined to be small and/or clustered in select regions of the country that have a lock on low-cost feedstock. To put the 2017 cost target into perspective of past accomplishments of the cellulosic ethanol pathway, the $80 target encompasses total delivered feedstock cost, including both grower payment and logistics costs, while meeting all

This article investigates upgrading biomass pyrolysis vapors to form hydrocarbon fuels and chemicals using catalysts with different concentrations of acid sites. It shows that greater separation of acid sites makes catalysts more efficient at producing hydrocarbon fuels and chemicals. The conversion of biomass into liquid transportation fuels has attracted significant attention because of depleting fossil fuel reserves and environmental concerns resulting from the use of fossil fuels. Biomass is a renewable resource, which is abundant worldwide and can potentially be exploited to produce transportation fuels that are less damaging to the environment. This renewable resource consists of cellulose (40–50%), hemicellulose (25–35%), and lignin (16–33%) biopolymers in addition to smaller quantities of inorganic materials such as silica and alkali and alkaline earth metals (calcium and potassium). Fast pyrolysis is an attractive thermochemical technology for converting biomass into precursors for hydrocarbon fuels because it produces up to 75 wt% bio-oil,1 which can be upgraded to feedstocks and/or blendstocks for further refining to finished fuels. Bio-oil that has not been upgraded has limited applications because of the presence of oxygen-containing functional groups, derived from cellulose, hemicellulose and lignin, which gives rise to high acidity, high viscosity, low heating value, immiscibility with hydrocarbons and aging during storage. Ex situ catalytic vapor phase upgrading is a promising approach for improving the properties of bio-oil. The goal of this process is to reject oxygen and produce a bio-oil with improved properties for subsequent downstream conversion to hydrocarbons.

With the aim to enhance the energy conversionefficiency of the rainbow shape piezoelectric transducer,an analysis model of energy conversionefficiency is established based on the elastic mechanics theory and piezoelectricity theory.It can be found that the energy conversionefficiency of the rainbow shape piezoelectric transducer mainly depends on its shape parameters and material properties from the analysis model.Simulation results show that there is an optimal length ratio to generate maximum energy conversionefficiency and the optimal length ratios and energy conversionefficiencies of beryllium bronze substrate transducer and steel substrate transducer are (0.65,2.21％) and (0.65,1.64％) respectively.The optimal thickness ratios and energy conversionefficiencies of beryllium bronze substrate transducer and steel substrate transducer are (1.16,2.56％) and (1.49,1.57％) respectively.With the increase of width ratio and initial curvature radius,both the energy conversionefficiencies decrease.Moreover,beryllium bronze flexible substrate transducer is superior to the steel flexible substrate transducer.

Advance recycling through pyrolytic technology has the potential of being applied to the management of plastic waste (PW). For this purpose 1 l volume, energy efficient batch reactor was manufactured locally and tested for pyrolysis of waste plastic. The feedstock for reactor was 50 g waste polyethylene. The average yield of the pyrolytic oil, wax, pyrogas and char from pyrolysis of PW were 48.6, 40.7, 10.1 and 0.6%, respectively, at 275 deg. C with non-catalytic process. Using catalyst the average yields of pyrolytic oil, pyrogas, wax and residue (char) of 50 g of PW was 47.98, 35.43, 16.09 and 0.50%, respectively, at operating temperature of 250 deg. C. The designed reactor could work at low temperature in the absence of a catalyst to obtain similar products as for a catalytic process.

The objective of this project was to develop an improved multistage process for the hydrothermal liquefaction (HTL) of biomass to serve as a new front-end, deconstruction process ideally suited to feed Virent’s well-proven catalytic technology, which is already being scaled up. This process produced water soluble, partially de-oxygenated intermediates that are ideally suited for catalytic finishing to fungible distillate hydrocarbons. Through this project, Virent, with its partners, demonstrated the conversion of pine wood chips to drop-in hydrocarbon distillate fuels using a multi-stage fractional conversion system that is integrated with Virent’s BioForming® process. The majority of work was in the liquefaction task and included temperature scoping, solvent optimization, and separations.

A dual-bed catalytic system is proposed for the direct conversion of methane to liquid hydrocarbons. In this system, methane is converted in the first stage to oxidative coupling of methane (OCM) products by selective catalytic oxidation with oxygen over La-supported MgO catalyst. The second bed, comprising of the HZSM-5 zeolite catalyst, is used for the oligomerization of OCM light hydrocarbon products to liquid hydrocarbons. The effects of temperature (650-800 ℃), methane to oxygen ratio (4-10), and SiO2/Al2O3 ratio of the HZSM-5 zeolite catalyst on the process are studied. At higher reaction temperatures, there is considerable dealumination of HZSM-5, and thus its catalytic performance is reduced. The acidity of HZSM-5 in the second bed is responsible for the oligomerization reaction that leads to the formation of liquid hydrocarbons. The activities of the oligomerization sites were unequivocally affected by the SiO2/Al2O3 ratio. The relation between the acidity and the activity of HZSM-5 is studied by means of TPD-NH3 techniques. The rise in oxygen concentration is not beneficial for the C5+ selectivity, where the combustion reaction of intermediate hydrocarbon products that leads to the formation of carbon oxide (CO+CO2) products is more dominant than the oligomerization reaction. The dual-bed catalytic system is highly potential for directly converting methane to liquid fuels.

This report describes one potential conversion process to hydrocarbon products by way of biological conversion of lingnocellulosic-dervied sugars. The process design converts biomass to a hydrocarbon intermediate, a free fatty acid, using dilute-acid pretreatement, enzymatic saccharification, and bioconversion. Ancillary areas--feed handling, hydrolysate conditioning, product recovery and upgrading (hydrotreating) to a final blendstock material, wastewater treatment, lignin combusion, and utilities--are also included in the design.

Microresonator-based Kerr frequency comb (microcomb) generation can potentially revolutionize a variety of applications ranging from telecommunications to optical frequency synthesis. However, phase-locked microcombs have generally had low conversionefficiency limited to a few percent. Here we report experimental results that achieve ~30% conversionefficiency (~200 mW on-chip comb power excluding the pump) in the fiber telecommunication band with broadband mode-locked dark-pulse combs. We present a general analysis on the efficiency which is applicable to any phase-locked microcomb state. The effective coupling condition for the pump as well as the duty cycle of localized time-domain structures play a key role in determining the conversionefficiency. Our observation of high efficiency comb states is relevant for applications such as optical communications which require high power per comb line.

We reported a coaxial,micro-dielectric barrier discharge(micro-DBD)reactor and a conventional DBD reactor for the direct conversion of methane into higher hydrocarbons at atmospheric pressure.The effects of input power,residence time,discharge gap and external electrode length were investigated for methane conversion and product selectivity.We found the conversion of methane in a micro-DBD reactor was higher than that in a conventional DBD reactor.And at an input power of 25.0 W,the conversion of methane and the total C2+C3 selectivity reached 25.10% and 80.27%,respectively,with a micro-DBD reactor of 0.4 mm discharge gap.Finally,a nonlinear multiple regression model was used to study the correlations between both methane conversion and product selectivity and various system variables.The calculated data were obtained using SPSS 12.0 software.The regression analysis illustrated the correlations between system variables and both methane conversion and product selectivity.

Highlights: • Low driving power conversionefficiency of natural circulation loops is proved. • The low conversionefficiency leads to low heat transfer capacity of such loops. • An efficiency booster is designed with turbine to increase the efficiency. • Performance of the proposed booster has been numerically simulated. • The booster drastically enhances heat transfer capacity of such loops. - Abstract: In this paper, the capacity of a natural circulation loop for transferring heat from a heat source to a heat sink has been analyzed. It is concluded that the capacity of the natural circulation loop depends on the conversionefficiency of the thermal energy from the heat source to the driving force for the circulation of the flow. The low conversionefficiency leading to weak driving force in such loops has been demonstrated analytically and validated through simulation results. This issue has resulted in a low heat transfer capacity in the circulation loop. To increase the heat transfer capacity, one has to improve this efficiency. To meet such a need, a novel efficiency booster has been developed in this paper. The booster essentially increases the flow driving force and hence significantly improves the overall heat transfer capacity. Design and analysis of this booster have been performed in detail. The performance has been examined through extensive computer simulations. It is concluded that the booster can indeed drastically improve the heat transfer capacity of the natural circulation loop.

Methane conversion to C2 hydrocarbons has been investigated with the addition of hydrogen in a plasma reactor of abnormal glow discharge at atmospheric pressure. The aim of this experiment is to minimize coke formation and improve discharge stability. The typical conditions in the experiment are 300 ml of total feed flux and 400 W of discharge power. The experimental results show that methane conversion is from 91.6% to 35.2% in mol, acetylene selectivity is from 90.2% to 57.6%, and ethylene selectivity is approximately from 7.8% to 3.6%,where the coke increases gradually along with the increase of CH4/H2 from 2: 8 to 9: 1. A stable discharge for a considerable running time can be obtained only at a lower ratio of CH4/H2= 2:8 or 3: 7. These phenomena indicate that the coke deposition during methane conversion is obviously reduced by adding a large amount of hydrogen during an abnormal glow discharge.A qualitative interpretation is presented, namely, with abundant hydrogen, the possibility that hydrogen molecules are activated to hydrogen radicals is increased with the help of the abnormal glow discharge. These hydrogen radicals react with carbon radicals to form C2 hydrocarbon products. Therefore, the deposition of coke is restrained.

Experiments are reported in which a methane plasma is created, and the methyl ions and hydrogen ions are accelerated within a microchannel array so that they interact with neutral methane molecules on the inside surfaces of the microchannels. No catalysts are used, and the device operates at room temperature. Impact energies of the ions are in the range of 10 eV to greater than 100 eV, and the energy delivered in the interaction at the surfaces causes the production of larger hydrocarbon molecules, such as C{sub 2}H{sub 2}, C{sub 2}H{sub 4}, and C{sub 2}H{sub 6}, along with C{sub 3}, C{sub 4}, C{sub 5}m C{sub 6}, C{sub 7}m and C{sub 8} molecules. There is a decreasing percentage of larger molecules produced, in comparison with the C{sub 2} and C{sub 3} types. Conversion effectiveness is greater at higher pressure, due to the increased ionic activity. The yield of the higher hydrocarbons depends upon the external voltage used, and voltage can be used as a control parameter to adjust the output mixture proportions. A conversion energy of 2.59 kilowatt hours/killogram of output has been demonstrated, and a reduction of this by a factor of 10 is possible using known techniques. In batch experiments, the selectivity for C{sub 2} has varied from 47% to 88%, and selectivity for C{sub 6} has ranged from 0% to 12.8%. Other hydrocarbon selectivities also span a wide and useful range. The estimated costs for hydrocarbons produced with this technology are in the range of $200 per tonne, in production quantities, depending upon natural gas costs. Pilot production experiments are recommended to make these estimates more precise, and to address strategies for scaling the technology up to production levels. Applications are discussed.

This report describes one potential conversion process to hydrocarbon products by way of catalytic conversion of lignocellulosic-derived hydrolysate. This model leverages expertise established over time in biomass deconstruction and process integration research at NREL, while adding in new technology areas for sugar purification and catalysis. The overarching process design converts biomass to die die diesel- and naphtha-range fuels using dilute-acid pretreatment, enzymatic saccharification, purifications, and catalytic conversion focused on deoxygenating and oligomerizing biomass hydrolysates.

In the literature on Sen's capability approach, studies focusing on the empirical measurement of conversion factors are comparatively rare. We add to this field by adopting a measure of 'conversionefficiency' that captures the efficiency with which individuals convert their resources into achieved

In the literature on Sen's capability approach, studies focusing on the empirical measurement of conversion factors are comparatively rare. We add to this field by adopting a measure of 'conversionefficiency' that captures the efficiency with which individuals convert their resources into achieved

Frequency conversion (FC) is an enabling process in many quantum information protocols. Recently, it has been observed that upconversion efficiencies in single-photon, mode-selective FC are limited to around 80%. In this Letter, we argue that these limits can be understood as time-ordering corrections (TOCs) that modify the joint conversion amplitude of the process. Furthermore, using a simple scaling argument, we show that recently proposed cascaded FC protocols that overcome the aforementioned limitations act as "attenuators" of the TOCs. This observation allows us to argue that very similar cascaded architectures can be used to attenuate TOCs in photon generation via spontaneous parametric downconversion. Finally, by using the Magnus expansion, we argue that the TOCs, which are usually considered detrimental for FC efficiency, can also be used to increase the efficiency of conversion in partially mode-selective FC.

Hybrid quantum networks rely on efficient interfacing of dissimilar quantum nodes, since elements based on parametric down-conversion sources, quantum dots, color centres or atoms are fundamentally different in their frequencies and bandwidths. While pulse manipulation has been demonstrated in very different systems, to date no interface exists that provides both an efficient bandwidth compression and a substantial frequency translation at the same time. Here, we demonstrate an engineered sum-frequency-conversion process in Lithium Niobate that achieves both goals. We convert pure photons at telecom wavelengths to the visible range while compressing the bandwidth by a factor of 7.47 under preservation of non-classical photon-number statistics. We achieve internal conversionefficiencies of 75.5%, significantly outperforming spectral filtering for bandwidth compression. Our system thus makes the connection between previously incompatible quantum systems as a step towards usable quantum networks.

The original concept envisioned for the use of Fischer-Tropsch processing (FTP) of United States associated natural gas in this study was to provide a way of utilizing gas which could not be brought to market because a pipeline was not available or for which there was no local use. Conversion of gas by FTP could provide a means of utilizing offshore associated gas which would not require installation of a pipeline or re-injection. The premium quality F-T hydrocarbons produced by conversion of the gas can be transported in the same way as the crude oil or in combination (blended) with it, eliminating the need for a separate gas transport system. FTP will produce a synthetic crude oil, thus increasing the effective size of the resource. The two conventional approaches currently used in US territory for handling of natural gas associated with crude petroleum production are re-injection and pipelining. Conversion of natural gas to a liquid product which can be transported to shore by tanker can be accomplished by FTP to produce hydrocarbons, or by conversion to chemical products such as methanol or ammonia, or by cryogenic liquefaction (LNG). This study considers FTP and briefly compares it to methanol and LNG. The Energy International Corporation cobalt catalyst, ratio adjusted, slurry bubble column F-T process was used as the basis for the study and the comparisons. An offshore F-T plant can best be accommodated by an FPSO (Floating Production, Storage, Offloading vessel) based on a converted surplus tanker, such as have been frequently used around the world recently. Other structure types used in deep water (platforms) are more expensive and cannot handle the required load.

We propose a new scheme of the resonant four-wave mixing (FWM) for the frequency up or down conversion, which is more efficient than the commonly-used scheme of the non-resonant FWM. In this new scheme, two control fields are spatially varied such that a probe field at the input can be converted to a signal field at the output. The efficiency of probe-to-signal energy conversion can be 90% at medium's optical depth of about 100. Our proposed scheme works for both the continuous-wave and pulse cases, and is flexible in choosing the control field intensity. This work provides a very useful tool in the nonlinear frequency conversion.

We propose an optical scheme, employing optical parametric down-converters interlaced with nonlinear sign gates (NSGs), that completely converts an n -photon Fock-state pump to n signal-idler photon pairs when the down-converters' crystal lengths are chosen appropriately. The proof of this assertion relies on amplitude amplification, analogous to that employed in Grover search, applied to the full quantum dynamics of single-mode parametric down-conversion. When we require that all Grover iterations use the same crystal, and account for potential experimental limitations on crystal-length precision, our optimized conversionefficiencies reach unity for 1 ≤n ≤5 , after which they decrease monotonically for n values up to 50, which is the upper limit of our numerical dynamics evaluations. Nevertheless, our conversionefficiencies remain higher than those for a conventional (no NSGs) down-converter.

Full Text Available We deduce a novel expression for the non-equilibrium photochemical potential and the power conversionefficiency of non-equilibrium light absorption by a thermostated material. Application of our results for the case of electron migration from valence to conduction bands in photovoltaic cells allows us to accurately interpolate experimental results for the maximal efficiencies of Ge-, Si-, GaAs-based cells and the like.

We develop and apply an effective analytic theory of a non-collinear, broadband type-I parametric down-conversion to study a coupling efficiency of the generated photon pairs into single mode optical fibers. We derive conditions necessary for highly efficient coupling for single and double type-I crystal producing polarization entangled states of light. We compare the obtained approximate analytic expressions with the exact numerical solutions and discuss the results for a case of BBO crystals.

Last year we demonstrated the microjet ballistic energy conversion system[1]. Here we show that the efficiency of such a system can be further improved by gate control. With gate control the electrical current generation is enhanced a hundred times with respect to the current generated from the zeta

It is suggested that using only 1 μm of silicon, sculpted in the form of a modulated nanowire photonic crystal, solar power conversionefficiency in the range of 15%-20% can be achieved. Choosing a specific modulation profile provides antireflection, light trapping, and back-reflection over broad angles in targeted spectral regions for high efficiency power conversion without solar tracking. Solving both Maxwell's equations in the 3D photonic crystal and the semiconductor drift-diffusion equations in each nanowire, we identify optimal junction and contact geometries and study the influence of the nanowire surface curvature on solar cell efficiency. We demonstrate that suitably modulated nanowires enable 20% efficiency improvement over their straight counterparts made of an equivalent amount of silicon. We also discuss the efficiency of a tandem amorphous and crystalline silicon nanowire photonic crystal solar cell. Opportunities for "hot carrier" collection and up-conversion of infrared light, enhanced by photonic crystal geometry, facilitate further improvements in power efficiency.

A mechanism is suggested for the acceleration by aromatic hydrocarbons of zeolite-catalyzed methanol conversion. According to this mechanism, the aromatic hydrocarbon undergoes successive ring methylation, prototropic conversion to an exo-methylene-cyclohexadiene, side-chain methylation, and ring de-ethylation. The overall result is that two methanol molecules give an ethylene molecule. The mechanism is supported by various reactions observed over ZSM-5 catalyst at methanol conversion temperatures: (I) deuteration of p-xylene by D/sub 2/O in the ring and methyl positions; (II) de-alkylation of p-ethyltoluene and n-propylbenzene; and (III) incorporation of the aromatic carbon of benzenes and alkylbenzenes into ethylene product, as revealed by /sup 13/C-labeling studies. 3 tables.

Full Text Available Efficientconversion of electrical energy from one form to another has always been a fascinating domain for researchers. Right from the era of mercury arc rectifiers to present AC-DC-AC two stage converters and cycloconverters, efforts are consistently being laid to minimize the losses involved in conversion process. In the present study the AC-AC conversion topology known as Matrix Converter (MC, is modeled using MATLAB. Venturini’s simplified algorithm is used to determine the switch modulation duty cycle. The model is designedfor conversion of 50 Hz input frequency to 100 Hz and 25 Hz, using a simplified switch modulation strategy. The waveforms generated by MATLAB/simulink confirm the reduction of conversion losses by 12% to 15% with use of proposed model as compared to conventional (PWM converters. It is not intended in this study just to list out various works done so for but to establish the brevity of fundamental concept representing the simplified design along with its application areas mainly the VFDs and Wind Energy Conversion Systems (WECS. The model has also been tested for control of induction motor with 100 HZ and 25 Hz output frequencies. The waveforms of changed frequencies and reduced losses confirm the results anticipated at design stage.

Hybrid quantum networks rely on efficient interfacing of dissimilar quantum nodes, as elements based on parametric downconversion sources, quantum dots, colour centres or atoms are fundamentally different in their frequencies and bandwidths. Although pulse manipulation has been demonstrated in very different systems, to date no interface exists that provides both an efficient bandwidth compression and a substantial frequency translation at the same time. Here we demonstrate an engineered sum-frequency-conversion process in lithium niobate that achieves both goals. We convert pure photons at telecom wavelengths to the visible range while compressing the bandwidth by a factor of 7.47 under preservation of non-classical photon-number statistics. We achieve internal conversionefficiencies of 61.5%, significantly outperforming spectral filtering for bandwidth compression. Our system thus makes the connection between previously incompatible quantum systems as a step towards usable quantum networks. PMID:28134242

Hybrid quantum networks rely on efficient interfacing of dissimilar quantum nodes, as elements based on parametric downconversion sources, quantum dots, colour centres or atoms are fundamentally different in their frequencies and bandwidths. Although pulse manipulation has been demonstrated in very different systems, to date no interface exists that provides both an efficient bandwidth compression and a substantial frequency translation at the same time. Here we demonstrate an engineered sum-frequency-conversion process in lithium niobate that achieves both goals. We convert pure photons at telecom wavelengths to the visible range while compressing the bandwidth by a factor of 7.47 under preservation of non-classical photon-number statistics. We achieve internal conversionefficiencies of 61.5%, significantly outperforming spectral filtering for bandwidth compression. Our system thus makes the connection between previously incompatible quantum systems as a step towards usable quantum networks.

A process and apparatus are provided for conversion of steam and hydrocarbon, or steam and coal, into a product gas which contains hydrogen. The conversion rate is augmented by effective extraction and removal of hydrogen as and when hydrogen is generated. Within a reaction vessel wherein the conversion takes place, a chamber for collection of hydrogen is formed by the provision of a hydrogen permeable membrane. The chamber is provided with a hydrogen extraction means and houses a support structure, for example, in the form of a mesh providing structural support to the membrane. The membrane may be of a pleated or corrugated construction, so as to provide an enlarged surface for the membrane to facilitate hydrogen extraction. Also, to further facilitate hydrogen extraction, a hydrogen partial pressure differential is maintained across the membrane, such as, for example, by the counter pressure of an inert gas. A preferred configuration for the apparatus of the invention is a tubular construction which houses generally tubular hydrogen extraction chambers. 5 figs.

As global energy consumption accelerates at an alarming rate, the development of clean and renewable energy conversion and storage systems has become more important than ever. Although the efficiency of energy conversion and storage devices depends on a variety of factors, their overall performance strongly relies on the structure and properties of the component materials. Nanotechnology has opened up new frontiers in materials science and engineering to meet this challenge by creating new materials, particularly carbon nanomaterials, for efficient energy conversion and storage. As a building block for carbon materials of all other dimensionalities (such as 0D buckyball, 1D nanotube, 3D graphite), the two-dimensional (2D) single atomic carbon sheet of graphene has emerged as an attractive candidate for energy applications due to its unique structure and properties. Like other materials, however, a graphene-based material that possesses desirable bulk properties rarely features the surface characteristics required for certain specific applications. Therefore, surface functionalization is essential, and researchers have devised various covalent and noncovalent chemistries for making graphene materials with the bulk and surface properties needed for efficient energy conversion and storage. In this Account, I summarize some of our new ideas and strategies for the controlled functionalization of graphene for the development of efficient energy conversion and storage devices, such as solar cells, fuel cells, supercapacitors, and batteries. The dangling bonds at the edge of graphene can be used for the covalent attachment of various chemical moieties while the graphene basal plane can be modified via either covalent or noncovalent functionalization. The asymmetric functionalization of the two opposite surfaces of individual graphene sheets with different moieties can lead to the self-assembly of graphene sheets into hierarchically structured materials. Judicious

A study of the deactivation and reactivation of modified clinoptilolite catalysts for methanol conversion to hydrocarbons is reported. Clinoptilolite catalysts, modified by either ammonium ion exchange or hydrochloric acid treatment, exhibit a short useful catalyst lifetime for this reaction (ca. 2-3 h) due to a high rate of coke deposition (3-5.10/sup -3/ g carbon/g catalyst/h). A comparative study of reactivation using oxygen, nitrous oxide and ozone/oxygen as oxidants indicated that nitrous oxide reactivation gives improved catalytic performance when compared to the activity and lifetime of the fresh catalyst. Both oxygen and ozone/oxygen were found to be ineffective for the reactivation of clinoptilolite. Initial studies of in situ on-line reactivation are also described. 3 figs., 15 refs., 4 tabs.

In recent years, oil production has increased enormously but almost half of the oil now remaining is heavy/biodegraded and cannot be put into production. There is therefore a need for new technology and for diversification of energy sources. This paper discusses the microbial conversion of higher hydrocarbons to methane in oil and coal reservoirs. The objective of the study is to identify microbial and geochemical controls on methanogenesis in reservoirs. A graph shows the utilization of methane for various purposes in Germany from 1998 to 2007. A degradation process to convert coal to methane is shown using a flow chart. The process for converting oil to methane is also given. Controlling factors include elements such as Fe, nitrogen and sulfur. Atmospheric temperature and reservoir pressure and temperature also play an important role. From the study it can be concluded that isotopes of methane provide exploration tools for reservoir selection and alkanes and aromatic compounds provide enrichment cultures.

It is shown that the propane molecules are strongly decomposed in the metal assisted laser induced plasma based on the nano-catalytic adsorption. A Q-Switched Nd:YAG laser is employed to irradiate the propane gas filled in the control chamber in the presence of the reactive metals such as Ni, Fe, Pd, and Cu in order to study the effect of catalysts during the decomposition. The catalytic targets simultaneously facilitate the plasma formation and the decomposition events leading to generate a wide distribution of the light and heavy hydrocarbon molecules, mainly due to the recombination processes. Fourier transform infrared spectroscopy and gas chromatography instruments support the findings by detecting the synthetic components. Furthermore, the optical emission spectroscopy of the laser induced plasma emissions realizes the real time monitoring of the reactions taking place during each laser shot. The subsequent recombination events give rise to the generation of a variety of the hydrocarbon molecules. The dissociation rate, conversion ratio, selectivity, and yield as well as the performance factor arise mainly from the catalytic effects of the metal species. Moreover, the ablation rate of the targets of interest is taken into account as a measure of the catalytic reactivity due to the abundance of the metal species ablated from the target. This leads to assess the better performance factor for Pd among four metal catalysts of interest during propane decomposition. Finally, the molecules such as ethane and ethylene are identified as the stable abundant species created during the successive molecular recombination processes.

Photon energy conversionefficiency coefficient is presented as the ratio of total energy registered in the collected spectrum to the emitted photon energy. This parameter is calculated from the conventional gamma-ray histogram and in principle is not affected by coincidence phenomena. This feature makes it particularly useful for calibration and measurement of radionuclide samples at close geometries. It complements the number of efficiency parameters used in gamma-ray spectrometry and can partly change the view as to how the gamma-ray spectra are displayed and processed.

Full Text Available Various metal-β zeolites have been synthesized under similar ion-exchange conditions. During the exchange process, the nature and acid strength of the used cations modified the composition and textural properties as well as the Brönsted and Lewis acidity of the final materials. Zeolites exchanged with divalent cations showed a clear decrease of their surface Brönsted acidity and an increase of their Lewis acidity. All materials were active as catalysts for the transformation of acetone into hydrocarbons. Although the protonic zeolite was the most active in the acetone conversion (96.8% conversion, the metal-exchanged zeolites showed varied selectivities towards different products of the reaction. In particular, we found the Cu-β to have a considerable selectivity towards the production of isobutene from acetone (over 31% yield compared to 7.5% of the protonic zeolite. We propose different reactions mechanisms in order to explain the final product distributions.

The scope of the present study was upgrading a set of heavy aromatic hydrocarbons mixtures whose commercial value ranks close to fuel oil and should become even lower in the next future because of the introduction of more stringent regulations on fuels, through hydro-conversion to a synthetic feed for steam-cracking. The resulting process provides an opportunity to improve the economic return of a steamcracking plant, offering the chance of converting low-value mixtures produced by the plant itself, such as fuel oil of cracking (FOK), saving an equivalent amount of naphtha. The method can also be used for converting pyrolysis gasoline (pygas). Although pygas has at present a fair commercial value, it could suffer a significant penalization in the future due to further limitations on total aromatic content in gasoline. Pygas hydro-conversion to a synthetic steam-cracking feedstock has been recently reported. Fractions from refinery, such as heavy distillates (e.g. Heavy Vacuum Gas Oil, VGO), deasphalted resides (DAO), or some FCC streams (e.g. LCO) resulted suitable and very attractive mixtures to be treated as well. No more than deasphalting was required as pretreatment of the feed mixture and only when the asphalts were >2%. Hetero-elements are often present in such kind of feeds at quite high concentrations, but no problems were observed due to the presence of sulphur and nitrogen, respectively, up to 15000 and 5500 ppm. (orig.)

Zeolites are the most commonly used catalysts for methanol-to-hydrocarbon (MTH) conversion. Here, we identified two oxygen-containing compounds as coke species in zeolite catalysts after MTH reactions. We investigated the possible influences of the oxygen-containing compounds on coke formation, catalyst deactivation, product selectivity, and the induction period of the MTH reaction through a series of controlled experiments in which one of the identified compounds (2,3-dimethyl-2-cyclopenten-1-one) was co-fed with methanol over a zeolite H-ZSM-5 catalyst. Our results allow us to infer that once produced, the oxygen-containing compounds block the Brønsted acid sites by strong chemisorption and their rapid conversion to aromatics expedites the formation of coke and thus the deactivation of the catalyst. A minor effect of the production of such compounds during the MTH reaction is that the aromatic-based catalytic cycle can be slightly promoted to give higher selectivity to ethylene.

The past five years have seen significant cost reductions in photovoltaics and a correspondingly strong increase in uptake, with photovoltaics now positioned to provide one of the lowest-cost options for future electricity generation. What is becoming clear as the industry develops is that area-related costs, such as costs of encapsulation and field-installation, are increasingly important components of the total costs of photovoltaic electricity generation, with this trend expected to continue. Improved energy-conversionefficiency directly reduces such costs, with increased manufacturing volume likely to drive down the additional costs associated with implementing higher efficiencies. This suggests the industry will evolve beyond the standard single-junction solar cells that currently dominate commercial production, where energy-conversionefficiencies are fundamentally constrained by Shockley-Queisser limits to practical values below 30%. This Review assesses the overall prospects for a range of approaches that can potentially exceed these limits, based on ultimate efficiency prospects, material requirements and developmental outlook.

The devices studied in this work consist of copper phthalocyanine (CuPc) and fullerene (C60) films between indium tin oxide (ITO) coated substrate as anode and aluminum (Al) as cathode. In order to have optimal performance of heterojunction photovoltaic cell, ITO/CuPc and C60/Al contact should be ohmic. Various ITO treatmetns can be used to improve ITO/CuPc contact. We have compared influence of different ITO treatments on the device performance. We have found that ITO treatmetn yields significant improvement in the performance of CuPc/C60 photovoltaic cells. The short circuit current of teh cell fabricated on ITO substrate with optimal treatment is 9 times larger than that of the cell fabricated on untreated ITO substrate, open circuit voltage has been increased by 0.12V, resulting in 12 times improvement in the power conversionefficiency. The performance of phthalocyanine solar cells can be further improved using a mixed layer structure, ITO/CuPc/CuPc:C60/Al, to increase exciton dissociation efficiency. The mixed layer is fabricated by co-evaporating the materials. For the mixed layer structure, short circuit current has been increased two times compared to the p-n heterojunction cell. This results in 0.16% power conversionefficiency under 98mW/cm2 AM1 solar irradiation.

Presently, the only commercially available power generating thermoelectric (TE) modules are based on bismuth telluride (Bi2Te3) alloys and are limited to a hot side temperature of 250 °C due to the melting point of the solder interconnects and/or generally poor power generation performance above this point. For the purposes of demonstrating a TE generator or TEG with higher temperature capability, we selected skutterudite based materials to carry forward with module fabrication because these materials have adequate TE performance and are mechanically robust. We have previously reported the electrical power output for a 32 couple skutterudite TE module, a module that is type identical to ones used in a high temperature capable TEG prototype. The purpose of this previous work was to establish the expected power output of the modules as a function of varying hot and cold side temperatures. Recent upgrades to the TE module measurement system built at the Fraunhofer Institute for Physical Measurement Techniques allow for the assessment of not only the power output, as previously described, but also the thermal to electrical energy conversionefficiency. Here we report the power output and conversionefficiency of a 32 couple, high temperature skutterudite module at varying applied loading pressures and with different interface materials between the module and the heat source and sink of the test system. We demonstrate a 7% conversionefficiency at the module level when a temperature difference of 460 °C is established. Extrapolated values indicate that 7.5% is achievable when proper thermal interfaces and loading pressures are used.

The constructive interference effect described by Fuchs et al. [1] shows that the mode conversion and thereby the overall heating efficiency can be enhanced significantly when an integer number of fast wave wavelengths can be folded in between the high field side fast wave cutoff and the ion-ion hybrid layer(s) at which the ion Bernstein or ion cyclotron waves are excited. This effect was already experimentally identified in (3He)-D plasmas [2] and was recently tested in (3He)-H JET plasmas. The latter is an `inverted' scenario, which differs significantly from the (3He)-D scenarios since the mode-conversion layer is positioned between the low field side edge of the plasma and the ion-cyclotron layer of the minority 3He ions (whereas the order in which a wave entering the plasma from the low field side encounters these layers is inverted in a `regular' scenario), and because much lower 3He concentrations are needed to achieve the mode-conversion heating regime. The presence of small amounts of 4He and D in the discharges gave rise to an additional mode conversion layer on top of the expected one associated with 3He-H, which made the interpretation of the results more complex but also more interesting: Three different regimes could be distinguished as a function of X[3He], and the differing dynamics at the various concentrations could be traced back to the presence of these two mode conversion layers and their associated fast wave cutoffs. Whereas (1-D and 2-D) numerical modeling yields quantitative information on the RF absorptivity, recent analytical work by Kazakov [3] permits to grasp the dominant underlying wave interaction physics.

The first edition of GaN Transistors for Efficient Power Conversion was self-published by EPC in 2012, and is currently the only other book to discuss GaN transistor technology and specific applications for the technology. More than 1,200 copies of the first edition have been sold through Amazon or distributed to selected university professors, students and potential customers, and a simplified Chinese translation is also available. The second edition has expanded emphasis on applications for GaN transistors and design considerations. This textbook provides technical and application-focused i

Full Text Available This study aims to develop the acoustoelectric conversion plate in terms of electromagnetic induction law to convert sound energy to electricity, where the developed apparatus is made of three parts, the thin film coil, the spring, and the high-intensity magnetic framework. In process, the thin film coil receives the injecting sound vibration in connection with the spring to cause the reciprocating motion between the coil and the high-intensity magnet, which yields the electromotive force (EMF. In this study, a pearl plate of length 95 mm, width 95 mm, and thickness 1.5 mm adhered with a PET film of thickness 0.08mm is built as the substrate plate due to it has good properties of light and elasticity. In connection with the substrate plate and the electric coil is the thin film coil. Experiments used the speaker with output frequencies of 30~156 Hz and sound power of 0.5 W (sound intensity 0.32 W/m2, sound pressure level 115 dB as the sound source. The sound energy is captured by the acoustoelectric conversion plate for working efficiency and optimization parameters analysis. The studied parameters content of diameter, turns, and width of electric coil as well as distance between high intensity magnet and coil. The results show that diameter 0.11 mm, turns 220, and width 3 mm of the electric coil, in connection with steel spring of diameter 0.2 mm while input sound is 30 Hz, receives the average output voltage of 0.57 V, the average output current of 5.46 mA, the average output power of 3.13 mW, and the sound electric conversionefficiency of 0.63%. This innovation device could be used in highway, near waterfalls, and some high noise factories to capture energy for immediately charging cell-phone to save human life.

A thermoelectric generator (TEG) efficiency booster with buck-boost conversion and power management is proposed as a TEG battery power conditioner suitable for a wide TEG output voltage range. An inverse-coupled inductor is employed in the buck-boost converter, which is used to achieve smooth current with low ripple on both the TEG and battery sides. Furthermore, benefiting from the magnetic flux counteraction of the two windings on the coupled inductor, the core size and power losses of the filter inductor are reduced, which can achieve both high efficiency and high power density. A power management strategy is proposed for this power conditioning system, which involves maximum power point tracking (MPPT), battery voltage control, and battery current control. A control method is employed to ensure smooth switching among different working modes. A modified MPPT control algorithm with improved dynamic and steady-state characteristics is presented and applied to the TEG battery power conditioning system to maximize energy harvesting. A 500-W prototype has been built, and experimental tests carried out on it. The power efficiency of the prototype at full load is higher than 96%, and peak efficiency of 99% is attained.

In searching for the optimum parameters that minimize the total life cycle cost of an energy conversion system, various combinations of components are examined and the resulting system performance and associated economics are studied. The systems performance and economics simulation computer program (SPECS) was developed to fill this need. The program simulates the fluid flow, thermal, and electrical characteristics of a system of components on a quasi-steady state basis for a variety of energy conversion systems. A unique approach is used in which the set of characteristic equations is solved by the Newton-Raphson technique. This approach eliminates the tedious iterative loops which are found in comparable programs such as TRNSYS or SOLTES-1. Several efficient features were also incorporated such as the centralized control and energy management scheme, and analogous treatment of energy flow in electrical and mechanical components, and the modeling of components of similar fundamental characteristics using generic subroutines. Initial tests indicate that this model can be used effectively with a relatively small number of time steps and low computer cost.

An improper ferroelectric is a certain type of ferroelectrics whose primary order parameter is not polarization but another physical quantity such as magnetization. In contrast to a conventional proper ferroelectrics as represented by Pb(Zr,Ti)O{sub 3} and BaTiO{sub 3}, the improper ferroelectrics has been inconceivable for practical applications thus far. Herein, we illustrate the great potential of improper ferroelectrics for efficientconversion of temperature fluctuation to electric energy, as demonstrated with (Ca{sub 0.84}Sr{sub 0.16}){sub 8}[AlO{sub 2}]{sub 12}(MoO{sub 4}){sub 2} (CSAM-16). The present study has experimentally proven that CSAM-16 achieves an excellent electrothermal coupling factor and high electric field sensitivity for pyroelectric energy conversion that approach a practical level for application to self-powered autonomous electronic devices for rapidly spreading wireless sensor networks. The present results provide a novel approach to developing innovative pyroelectric energy harvesting devices using improper ferroelectrics. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Oecophylla ants are sold at high prices on several commercial markets as a human delicacy, as pet food or as traditional medicine. Currently markets are supplied by ants collected from the wild; however, an increasing interest in ant farming exists as all harvest is easily sold and as ant farming...... can be combined with the use of the ants in biological control programmes in tropical plantations where pest insects are converted into ant biomass. To assess the cost-benefits of ant farming based on artificial feeding, food consumption and food conversionefficiency (ECI) of Oecophylla smaragdina...... (Fabricius) was tested under laboratory conditions. Of the two types of food offered, the ants ingested 76% pure sucrose and 24% insect prey (dry weights) leading to ECI’s of 29% and 39% including brood only or brood plus imago gain, respectively. Based on Thai sugar and protein food costs and ant brood...

Tandem photovoltaic cells, as proposed by Jackson (1955) to increase the efficiency of solar energy conversion, involve the construction of a system of stacked p/n homojunction photovoltaic cells composed of different semiconductors. It had been pointed out by critics, however, that the total power which could be extracted from the cells in the stack placed side by side was substantially greater than the power obtained from the stacked cells. A reexamination of the tandem cell concept in view of the development of the past few years is conducted. It is concluded that the use of tandem cell systems in flat plate collectors, as originally envisioned by Jackson, may yet become feasible as a result of the development of economically acceptable solar cells for large scale terrestrial power generation.

Beaming effect makes it possible that gamma-ray bursts have a standard energy,but the gamma-ray energy release is sensitive to some parameters.Our attention is focused on the effect of the gamma ray conversionefficiency(ηγ),which may range between 0.01 and 0.9,and which probably has a random value for different GRBs under certain conditions.Making use of the afterglow data from the literature,we carried out a complete correction to the conical opening angle formula.Within the framework of the conical jet model,we ran a simple Monte Carlo simulation for random values of ηγ,and found that the gamma-ray energy release is narrowly clustered,whether we use a constant value of ηγ or random values for different gamma-ray bursts.

Tandem photovoltaic cells, as proposed by Jackson (1955) to increase the efficiency of solar energy conversion, involve the construction of a system of stacked p/n homojunction photovoltaic cells composed of different semiconductors. It had been pointed out by critics, however, that the total power which could be extracted from the cells in the stack placed side by side was substantially greater than the power obtained from the stacked cells. A reexamination of the tandem cell concept in view of the development of the past few years is conducted. It is concluded that the use of tandem cell systems in flat plate collectors, as originally envisioned by Jackson, may yet become feasible as a result of the development of economically acceptable solar cells for large scale terrestrial power generation.

X-ray sources in the 3-7 keV energy regime can be produced by laser-irradiating mid- and high-Z gas-filled targets with high-powered lasers. A series of experiments have been performed using underdense targets that are supersonically heated with {approx} 35 kJ of 0.35 {micro}m laser light. These targets were cylindrical Be enclosures that were filled with 1-2 atms of Xe or Ar gas. L-shell x-ray emission is emitted from the plasma and detected by Bragg crystal spectrometers and x-ray diodes. Absolute flux measurements show conversionefficiencies of {approx} 10% in the multi-kilovolt x-ray emission. These sources can be used as bright x-ray backlighters or for material testing.

(Fabricius) was tested under laboratory conditions. Of the two types of food offered, the ants ingested 76% pure sucrose and 24% insect prey (dry weights) leading to ECI’s of 29% and 39% including brood only or brood plus imago gain, respectively. Based on Thai sugar and protein food costs and ant brood......Oecophylla ants are sold at high prices on several commercial markets as a human delicacy, as pet food or as traditional medicine. Currently markets are supplied by ants collected from the wild; however, an increasing interest in ant farming exists as all harvest is easily sold and as ant farming...... can be combined with the use of the ants in biological control programmes in tropical plantations where pest insects are converted into ant biomass. To assess the cost-benefits of ant farming based on artificial feeding, food consumption and food conversionefficiency (ECI) of Oecophylla smaragdina...

A method for producing a hydrocarbon blendstock, the method comprising contacting at least one saturated acyclic alcohol having at least three and up to ten carbon atoms with a metal-loaded zeolite catalyst at a temperature of at least 100°C and up to 550°C, wherein the metal is a positively-charged metal ion, and the metal-loaded zeolite catalyst is catalytically active for converting the alcohol to the hydrocarbon blendstock, wherein the method directly produces a hydrocarbon blendstock having less than 1 vol % ethylene and at least 35 vol % of hydrocarbon compounds containing at least eight carbon atoms.

With increasing demand for chemicals and fuels, and finite traditional crude oil resources, there is a growing need to invent, establish, or optimize chemical processes that convert gasifiable carbon-based feedstocks (e.g., coal, natural gas, oil sands, or biomass) into the needed final products. Catalysis is central to almost every industrial chemical process, including alkane metathesis (AM) and the methanol-to-hydrocarbons (MTH) process, which represent final steps in a sequence of hydrocarbonconversion reactions. An in depth understanding of AM and MTH is essential to the selective production of the desired end products. In this dissertation, ab initio density functional theory simulations provide unique mechanistic and thermodynamic insight of specific elementary steps involved in AM and MTH as performed on zeolite supports. Zeolites have been employed throughout the petroleum industry because of their ability to perform acid-catalyzed reactions (e.g., cracking or MTH). The crystalline structure of zeolites imparts regular microporous networks and, in turn, the selective passage of molecules based on shape and functionality. Many different elements can be grafted onto or substituted into zeolites, resulting in a broad range of catalytic behavior. However, due to the variety of competing and secondary reactions that occur at experimental conditions, it is often difficult to extract quantitative information regarding individual elementary steps. ab initio calculations can be particularly useful for this purpose. Alkane metathesis (i.e., the molecular redistribution or chain length averaging of alkanes) is typically performed by transition metal hydrides on amorphous alumina or silica supports. In Chapter 3, the feasibility of AM in zeolites is assessed by using a grafted Ta-hydride complex to explore the full catalytic cycle in the self-metathesis of ethane. The decomposition of a Ta-metallacyclobutane reaction intermediate that forms during olefin metathesis

Systems, processes, and catalysts are disclosed for obtaining fuel and fuel blends containing selected ratios of open-chain and closed-chain fuel-range hydrocarbons suitable for production of alternate fuels including gasolines, jet fuels, and diesel fuels. Fuel-range hydrocarbons may be derived from ethylene-containing feedstocks and ethanol-containing feedstocks.

The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytb⁢c1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversionefficiency of ATP synthesis at illuminations corresponding to 1%-5% of full sunlight is calculated to be 0.12-0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination.

The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytb⁢c1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversionefficiency of ATP synthesis at illuminations corresponding to 1%–5% of full sunlight is calculated to be 0.12–0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination. DOI: http://dx.doi.org/10.7554/eLife.09541.001 PMID:27564854

Biomass is uniquely able to supply renewable and sustainable liquid transportation fuels. In the near term, the Biomass program has a 2012 goal of cost competitive cellulosic ethanol. However, beyond 2012, there will be an increasing need to provide liquid transportation fuels that are more compatible with the existing infrastructure and can supply fuel into all transportation sectors, including aviation and heavy road transport. Microbial organisms are capable of producing a wide variety of fuel and fuel precursors such as higher alcohols, ethers, esters, fatty acids, alkenes and alkanes. This report surveys liquid fuels and fuel precurors that can be produced from microbial processes, but are not yet ready for commercialization using cellulosic feedstocks. Organisms, current research and commercial activities, and economics are addressed. Significant improvements to yields and process intensification are needed to make these routes economic. Specifically, high productivity, titer and efficientconversion are the key factors for success.

Full Text Available The intrinsic biodegradability of hydrocarbons and the distribution of proficient degrading microorganisms in the environment are very crucial for the implementation of bioremediation practices. Among others, one of the most favorable methods that can enhance the effectiveness of bioremediation of hydrocarbon-contaminated environment is the application of biosurfactant producing microbes. In the present study, the biodegradation capacities of native bacterial consortia towards total petroleum hydrocarbons (TPH with special emphasis to poly aromatic hydrocarbons (PAHs were determined. The purpose of the study was to isolate TPH degrading bacterial strains from various petroleum contaminated soil of Assam, India and develop a robust bacterial consortium for bioremediation of crude oil of this native land. From a total of 23 bacterial isolates obtained from three different hydrocarbons contaminated samples 5 isolates, namely KS2, PG1, PG5, R1 and R2 were selected as efficient crude oil degraders with respect to their growth on crude oil enriched samples. Isolates KS2, PG1 and R2 are biosurfactant producers and PG5, R1 are non-producers. Fourteen different consortia were designed involving both biosurfactant producing and non-producing isolates. Consortium 10, which comprises two Bacillus strains namely, Bacillus pumilus KS2 and Bacillus cereus R2 (identified by 16s rRNA sequencing has shown the best result in the desired degradation of crude oil. The consortium showed degradation up to 84.15% of total petroleum hydrocarbon (TPH after five weeks of incubation, as revealed from gravimetric analysis. FTIR (Fourier transform infrared and GCMS (Gas chromatography-mass spectrometer analyses were correlated with gravimetric data which reveals that the consortium has removed a wide range of petroleum hydrocarbons in comparison with abiotic control including different aliphatic and aromatic hydrocarbons.

Solar cells are expected to provide environmentally friendly solutions to the world`s energy supply problem. Learning from the concepts used by green plants we have developed a molecular photovoltaic device whose overall efficiency for AM 1.5 solar light to electricity has already attained 8-11%. The system is based on the sensitization of nanocrystalline oxide films by transition metal charge transfer sensitizers. In analogy to photosynthesis, the new chemical solar cell achieves the separation of the light absorption and charge carrier transport processes. Extraordinary yields for the conversion of incident photons into electric current are obtained, exceeding 90% for transition metal complexes within the wavelength range of their absorption band. The use of molten salt electrolytes together with coordination complexes of ruthenium as sensitizers and adequate sealing technology has endowed these cells with a remarkable stability making practical applications feasible. Seven industrial cooperations are presently involved in the development to bring these cells to the market. The first cells will be applied to supply electric power for consumer electronic devices. The launching of production of several products of this type is imminent and they should be on the market within the next two years. Quite aside from their intrinsic merits as photovoltaic device, the mesoscopic oxide semiconductor films developed in our laboratory offer attractive possibilities for a number of other applications. Thus, the first example of a nanocrystalline rocking chair battery will be demonstrated and its principle briefly discussed.

This yearly report for the Swiss Federal Office of Energy (SFOE) takes a look at the work done in 2005 and the work planned for 2006 within the framework of the Efficient Energy Conversion in the Pulp and Paper Industry project. The results of investigations made at a large pulp and paper facility in Switzerland are presented and analysed. Data models of the steam and condensate networks and of the processes involved are examined. An additional model of the sulphur loop has been also elaborated. From this analysis, a list of required measurements has been developed. Several performance indicators have also been calculated: A systematic analysis method developed to identify sections where condensate could be recovered is discussed. A systematic definition of the hot and cold streams in the process is being developed in order to compute the minimum energy requirements of the process. Evaluating this minimum energy requirement from the data available is to be used to prepare definitions of the energy savings possible.

Calculated results are presented for the energy, number of photons, and conversionefficiency for high-order harmonic generation in helium. The results show the maximum values that we should expect to achieve experimentally with our current apparatus and the important parameters for scaling this source to higher output. In the desired operating regime where the coherence length, given by L{sub coh}={pi}b/(q-1), is greater than the gas column length, l, the harmonic output can be summarized by a single equation: N{sub q}=[({pi}{sup z}n{sup z}b{sup 3}{tau}{sub q}{vert_bar}d{sub q}{vert_bar}{sup z})/4h]{l_brace}(p/q)(2l/b){sup z}{r_brace}. N{sub q} - numbers of photons of q-th harmonic; n - atom density; b - laser confocal parameter; {tau}{sub q} - pulse width of harmonic radiation; q - harmonic order; p - effective order of nonlinearity. (Note the term in brackets, the phase-matching function, has been separated from the rest of the expression in order to be consistent with the relevant literature).

Calculated results are presented for the energy, number of photons, and conversionefficiency for high-order harmonic generation in helium. The results show the maximum values that we should expect to achieve experimentally with our current apparatus and the important parameters for scaling this source to higher output. In the desired operating regime where the coherence length, given by L[sub coh]=[pi]b/(q-1), is greater than the gas column length, l, the harmonic output can be summarized by a single equation: N[sub q]=[([pi][sup z]n[sup z]b[sup 3][tau][sub q][vert bar]d[sub q][vert bar][sup z])/4h][l brace](p/q)(2l/b)[sup z][r brace]. N[sub q] - numbers of photons of q-th harmonic; n - atom density; b - laser confocal parameter; [tau][sub q] - pulse width of harmonic radiation; q - harmonic order; p - effective order of nonlinearity. (Note the term in brackets, the phase-matching function, has been separated from the rest of the expression in order to be consistent with the relevant literature).

Direct conversion of methane using a metal-loaded ZSM-5 zeolite prepared via acidic ion exchange was investigated to elucidate the roles of metal and acidity in the formation of liquid hydrocarbons. ZSM-5 (SiO2/Al2O3=30) was loaded with different metals (Cr, Cu and Ga) according to the acidic ion-exchange method to produce metal-loaded ZSM-5 zeolite catalysts. XRD, NMR, FT-IR and N2 adsorption analyses indicated that Cr and Ga species managed to occupy the aluminum positions in the ZSM-5 framework. In addition, Cr species were deposited in the pores of the structure. However, Cu oxides were deposited on the surface and in the mesopores of the ZSM-5 zeolite. An acidity study using TPD-NH3, FT-IR, and IR-pyridine analyses revealed that the total number of acid sites and the strengths of the Bronsted and Lewis acid sites were significantly different after the acidic ion exchange treatment.Cu loaded HZSM-5 is a potential catalyst for direct conversion of methane to liquid hydrocarbons. The successful production of gasoline via the direct conversion of methane depends on the amount of aluminum in the zeolite framework and the strength of the Bronsted acid sites.

A theoretical analysis of an ultra-short pulse converted to Terahertz radiation via optical rectification in nonlinear optical crystal is presented here;several factors that affect optical-to-THz conversionefficiencies are discussed;pulse durations affect the conversionefficiency effectively:when crystal length is equal to the optimal crystal length lc,optical-to-THz conversionefficiency is the highest,but for the periodically-inverted electro-optic crystals,conversionefficiency is almost proportional to the crystal length when absorption can be neglected.Taking account of the absorption of crystals,effective length of crystal is Leff=0.63/α,there is no apparent increase of conversionefficiency and the conversionefficiency approaches to a constant eventually when the crystal length is increased.

This project explored conversion of methane to useful products by two techniques that do not involve oxidative coupling. The first approach was direct catalytic dehydrocoupling of methane to give hydrocarbons and hydrogen. The second approach was oxidation of methane to methanol by using heterogenized versions of catalysts that were developed as homogeneous models of cytochrome-P450, an enzyme that actively hydroxylates hydrocarbons by using molecular oxygen. Two possibilities exist for dehydrocoupling of methane to higher hydrocarbons: The first, oxidative coupling to ethane/ethylene and water, is the subject of intense current interest. Nonoxidative coupling to higher hydrocarbons and hydrogen is endothermic, but in the absence of coke formation the theoretical thermodynamic equilibrium yield of hydrocarbons varies from 25% at 827{degrees}C to 65% at 1100{degrees}C (at atmospheric pressure). In this project we synthesized novel, highly dispersed metal catalysts by attaching metal clusters to inorganic supports. The second approach mimics microbial metabolism of methane to produce methanol. The methane mono-oxygenase enzyme responsible for the oxidation of methane to methanol in biological systems has exceptional selectivity and very good rates. Enzyme mimics are systems that function as the enzymes do but overcome the problems of slow rates and poor stability. Most of that effort has focused on mimics of cytochrome P-450, which is a very active selective oxidation enzyme and has a metalloporphyrin at the active site. The interest in nonporphyrin mimics coincides with the interest in methane mono-oxygenase, whose active site has been identified as a {mu}-oxo dinuclear iron complex.We employed mimics of cytochrome P-450, heterogenized to provide additional stability. The oxidation of methane with molecular oxygen was investigated in a fixed-bed, down-flow reactor with various anchored metal phthalocyanines (PC) and porphyrins (TPP) as the catalysts.

Nanoparticle (NP) mediated photothermal effect shows great potential as a noninvasive method for cancer therapy treatment, but the development of photothermal agents with high photothermal conversionefficiency, small size and good biocompatibility is still a big challenge. Herein, we report Pd NPs with a porous structure exhibiting enhanced near infrared (NIR) absorption as compared to Pd nanocubes with a similar size (almost two-fold enhancement with a molar extinction coefficient of 6.3 × 10(7) M(-1) cm(-1)), and the porous Pd NPs display monotonically rising absorbance from NIR to UV-Vis region. When dispersed in water and illuminated with an 808 nm laser, the porous Pd NPs give a photothermal conversionefficiency as high as 93.4%, which is comparable to the efficiency of Au nanorods we synthesized (98.6%). As the porous Pd NPs show broadband NIR absorption (650-1200 nm), this allows us to choose multiple laser wavelengths for photothermal therapy. In vitro photothermal heating of HeLa cells in the presence of porous Pd NPs leads to 100% cell death under 808 nm laser irradiation (8 W cm(-2), 4 min). For photothermal heating using 730 nm laser, 70% of HeLa cells were killed after 4 min irradiation at a relative low power density of 6 W cm(-2). These results demonstrated that the porous Pd nanostructure is an attractive photothermal agent for cancer therapy.

Two-dimensional (2D) transition-metal (groups IV, V, VI) carbides (MXenes) with formulas M3C2 have been investigated as CO2 conversion catalysts with well-resolved density functional theory calculations. While MXenes from the group IV to VI series have demonstrated an active behavior for the capture of CO2, the Cr3C2 and Mo3C2 MXenes exhibit the most promising CO2 to CH4 selective conversion capabilities. Our results predicted the formation of OCHO(•) and HOCO(•) radical species in the early hydrogenation steps through spontaneous reactions. This provides atomic level insights into the computer-aided screening for high-performance catalysts and the understanding of electrochemical mechanisms for CO2 reduction to energy-rich hydrocarbon fuels, which is of fundamental significance to elucidate the elementary steps for CO2 fixation.

The intrinsic biodegradability of hydrocarbons and the distribution of proficient degrading microorganisms in the environment are very crucial for the implementation of bioremediation practices. Among others, one of the most favorable methods that can enhance the effectiveness of bioremediation of hydrocarbon-contaminated environment is the application of biosurfactant producing microbes. In the present study, the biodegradation capacities of native bacterial consortia toward total petroleum hydrocarbons (TPH) with special emphasis to poly aromatic hydrocarbons were determined. The purpose of the study was to isolate TPH degrading bacterial strains from various petroleum contaminated soil of Assam, India and develop a robust bacterial consortium for bioremediation of crude oil of this native land. From a total of 23 bacterial isolates obtained from three different hydrocarbons contaminated samples five isolates, namely KS2, PG1, PG5, R1, and R2 were selected as efficient crude oil degraders with respect to their growth on crude oil enriched samples. Isolates KS2, PG1, and R2 are biosurfactant producers and PG5, R1 are non-producers. Fourteen different consortia were designed involving both biosurfactant producing and non-producing isolates. Consortium 10, which comprises two Bacillus strains namely, Bacillus pumilus KS2 and B. cereus R2 (identified by 16s rRNA sequencing) has shown the best result in the desired degradation of crude oil. The consortium showed degradation up to 84.15% of TPH after 5 weeks of incubation, as revealed from gravimetric analysis. FTIR (Fourier transform infrared) and GCMS (Gas chromatography-mass spectrometer) analyses were correlated with gravimetric data which reveals that the consortium has removed a wide range of petroleum hydrocarbons in comparison with abiotic control including different aliphatic and aromatic hydrocarbons.

National Aeronautics and Space Administration — We will develop a power conversion solution that will increase end-to-end efficiency to 80% or more compared to the 30%-50% efficiency typically obtained through use...

The catalytic cracking of palm oil to liquid hydrocarbon fuels was studied in a fixed bed micro-reactor operated at atmospheric pressure, reaction temperature of 723 K and weight hourly space velocity (WHSV) of 2.5 h{sup -1} over the synthesized mesoporous molecular sieve MCM-41 materials. Mesoporous aluminosilicate with Si/Al ratio of 50 was synthesized using the hydrothermal method. Different pore sizes were obtained by changing the type of template and organic directing agent (ODA) used. The synthesized materials were characterized using various analytical methods such as X-ray powder diffraction (XRD), BET surface area, inductive coupled plasma (ICP), MAS NMR, FTIR and temperature-programmed desorption (TPD). The materials exhibit a crystalline structure of MCM-41 mesoporous molecular sieves with surface area varying from 550 to 1200 m{sup 2}/g and an average pore size (APS) ranging from 1.8 to 2.8 nm. The synthesized MCM-41 catalysts show high activity for palm oil cracking. The conversion of palm kernel oil, lower-molecular-weight oil, was higher as compared to higher-molecular-weight, palm olein oil. MCM-41 materials were selective for the formation of linear hydrocarbons, particularly, C{sub 13} when palm kernel oil was used and C{sub 17} when palm olein oil was fed. The yield of liquid product decreased with the increase of surface area of the catalyst. The gasoline selectivity increased whereas diesel selectivity decreased with the conversion of palm oil.

Zeolite catalyzed deoxygenation of small oxygenates present in bio-oil or selected as model compounds was performed under Methanol-to-Hydrocarbons (MTH) like reaction conditions using H-ZSM-5 as the catalyst. Co-feeding of the oxygenates with methanol generally decreases catalyst lifetime due to ...

The catalytic conversion of CO2 into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO2 conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO2 conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au25 nanoclusters as renewably powered CO2 conversion electrocatalysts with CO2 → CO reaction rates between 400 and 800 L of CO2 per gram of catalytic metal per hour and product selectivities between 80 and 95%. These performance metrics correspond to conversion rates approaching 0.8-1.6 kg of CO2 per gram of catalytic metal per hour. We also present data showing CO2 conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 10(6) molCO2 molcatalyst(-1) during a multiday (36 h total hours) CO2 electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 10(6) and 4 × 10(6) molCO2 molcatalyst(-1) were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO2 conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO2 conversion technologies. Specifically, we show the following: (1) all electrochemical CO2 conversion systems will produce a net increase in CO2 emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies are sufficient

Emission control devices on dryers and presses have been legislated into the industry, and are now an integral part of the drying system. These devices consume large quantities of natural gas and electricity and down-sizing or eliminating them will provide major energy savings. The principal strategy taken here focuses on developing process changes that should minimize (and in some cases eliminate) the need for controls. A second approach is to develop lower-cost control options. It has been shown in laboratory and full-scale work that Hazardous Air Pollutants (HAPs) emerge mainly at the end of the press cycle for particleboard, and, by extension, to other prod-ucts. Hence, only the air associated with this point of the cycle need be captured and treated. A model for estimating terpene emissions in the various zones of veneer dryers has been developed. This should allow the emissions to be concentrated in some zones and minimized in others, so that some of the air could be directly released without controls. Low-cost catalysts have been developed for controlling HAPs from dryers and presses. Catalysts conventionally used for regenerative catalytic oxidizers can be used at much lower temperatures for treating press emissions. Fluidized wood ash is an especially inexpensive mate-rial for efficiently reducing formaldehyde in dryer emissions. A heat transfer model for estimating pinene emissions from hot-pressing strand for the manufacture of flakeboard has been constructed from first principles and validated. The model shows that most of the emissions originate from the 1-mm layer of wood adjoining the platen surface. Hence, a simple control option is to surface a softwood mat with a layer of hardwood prior to pressing. Fines release a disproportionate large quantity of HAPs, and it has been shown both theo-retically and in full-scale work that particles smaller than 400 ÃÂÃÂµm are principally responsible. Georgia-Pacific is considering green

Motivated by the goal of finding improved catalysts for low- temperature conversion of light alkanes into fuel components or precursors of fuel components, the researchers have investigated sulfated zirconia and promoted sulfated zirconia for conversion of butane, propane, and ethane. Catalyst performance data for sulfated zirconia promoted with iron and manganese show that it is the most active noncorrosive, nonhalide catalyst known for n-butane isomerization, and it is an excellent candidate catalyst for new low- temperature n-butane isomerization processes to make isobutane, which can be converted by established technology into methyl t-butyl ether (MTBE). Various transition metals have been found to work as promoters of sulfated zirconia for n-butane isomerization. The combination of iron and manganese is the best known combination of promoters yet discovered. The iron- and manganese-promoted sulfated zirconia is also a catalyst for conversion of propane and of ethane. Ethane is converted into ethylene and butanes in the presence of the iron- and manganese-promoted sulfated zirconia; propane is also converted into butane, among other products. However, the activities of the catalyst for these reactions are orders of magnitude less than the activity for n-butane conversion, and there is no evidence that the catalyst would be of practical value for conversion of alkanes lighter than butane. The product distribution data for ethane and propane conversion provide new insights into the nature of the catalyst and its acidity. These data suggest the involvement of Olah superacid chemistry, whereby the catalyst protonates the alkane itself, giving carbonium ions (as transition states). The mechanism of protonation of the alkane may also pertain to the conversion of butane, but there is good evidence that the butane conversion also proceeds via alkene intermediates by conventional mechanisms of carbenium ion formation and rearrangement.

The ecological conversionefficiencies in twelve species of fish in the Yellow Sea Ecosystem, i.e., anchovy ( Engraulis japonicus), rednose anchovy ( Thrissa kammalensis), chub mackerel ( Scomber japonicus), halfbeak ( Hyporhamphus sajori), gizzard shad ( Konosirus punctatus), sand lance ( Ammodytes personatus), red seabream ( Pagrus major), black porgy ( Acanthopagrus schlegeli), black rockfish ( Sebastes schlegeli), finespot goby ( Chaeturichthys stigmatias), tiger puffer ( Takifugu rubripes), and fat greenling ( Hexagrammos otakii), were estimated through experiments conducted either in situ or in a laboratory. The ecological conversionefficiencies were significantly different among these species. As indicated, the food conversionefficiencies and the energy conversionefficiencies varied from 12.9% to 42.1% and from 12.7% to 43.0%, respectively. Water temperature and ration level are the main factors influencing the ecological conversionefficiencies of marine fish. The higher conversionefficiency of a given species in a natural ecosystem is acquired only under the moderate environment conditions. A negative relationship between ecological conversionefficiency and trophic level among ten species was observed. Such a relationship indicates that the ecological efficiency in the upper trophic levels would increase after fishing down marine food web in the Yellow Sea ecosystem.

Background: Efficacy studies have demonstrated the benefit of group conversation therapy for a person with aphasia (PWA). However, a PWA typically participates in individual therapy prior to group therapy. Stimulation therapy (ST) is the most common type of individual aphasia therapy. Ultimately, the outcome of therapy is to enable the PWA to…

Buckling is one of the most common phenomena in atomic-thick layered structures like graphene. While the buckling phenomenon usually causes disaster for most nano-devices, we illustrate one positive application of the buckled graphene for energy harvest, storage, and conversion. More specifically, we perform molecular dynamical simulations to show that the buckled graphene can be used to collect the wasted mechanical energy and store the energy in the form of internal knotting potential. Thro...

Mitigation of petroleum hydrocarbons was investigated during a 5-month greenhouse experiment, to assess the rhizoremediation (RR) potential in sediments with different characteristics colonized by Juncus maritimus, a salt marsh plant commonly found in temperate estuaries. Furthermore, the efficiency of two bioremediation treatments namely biostimulation (BS) by the addition of nutrients, and bioaugmentation (BA) by addition of indigenous microorganisms, was tested in combination with RR. The effect of the distinct treatments on hydrocarbon degradation, root biomass weight, and bacterial community structure was assessed. Our result showed higher potential for hydrocarbon degradation (evaluated by total petroleum hydrocarbon analysis) in coarse rhizosediments with low organic matter (OM), than rhizosediments with high OM, and small size particles. Moreover, the bacterial community structure was shaped according to the rhizosediment characteristics, highlighting the importance of specific microbe-particle associations to define the structure of rhizospheric bacterial communities, rather than external factors, such as hydrocarbon contamination or the applied treatments. The potential for hydrocarbon RR seems to depend on root system development and bacterial diversity, since biodegradation efficiencies were positively related with these two parameters. Treatments with higher root biomass, and concomitantly with higher bacterial diversity yielded higher hydrocarbon degradation. Moreover, BS and BA did not enhance hydrocarbons RR. In fact, it was observed that higher nutrient availability might interfere with root growth and negatively influence hydrocarbon degradation performance. Therefore, our results suggested that to conduct appropriate hydrocarbon bioremediation strategies, the effect of sediment characteristics on root growth/exploration should be taken into consideration, a feature not explored in previous studies. Furthermore, strategies aiming for the recovery

To properly design and assess a piezoelectric vibration energy harvester, it is necessary to consider the application of an efficiency measure of energy conversion. The energy conversionefficiency is defined in this work as the ratio of the electrical output power to the mechanical input power for a piezoelectric vibration energy harvester with an impedance-matched load resistor. While previous research works employed the electrical output power for approximate impedance-matched load resistance, this work derives an efficiency measure considering optimally matched resistance. The modified efficiency measure is validated by comparing it with finite element analysis results for piezoelectric vibration energy harvesters with three different values of the electro-mechanical coupling coefficient. New findings on the characteristics of energy conversion and conversionefficiency are also provided for the two different impedance matching methods.

Direct conversion of methane into C2 hydrocarbons through alternating current electric field enhanced plasma was studied under room temperature, atmospheric pressure and low power conditions.The distribution of electrical field intensity and distribution of energy were calculated with software that was developed by us according to the charge simulation method. The results indicated that the energy of tip of electrode was 0.36 J/mm3 and it was higher than the methane dissociation energy (0.0553 J/mm3).The methane located at this area can be activated easily. The higher-energy particles produced by dissociation collided with molecules around them and initiated consecutive reactions between free radicals and molecules. The method was proved to be valided and could be taken as a basis for the electrical field study concerned.

Although solar photovoltaic conversionefficiencies over 30 percent (one sun, AM1) can be expected for multiple-cell configurations using spectral splitting techniques, the highest practical single-cell conversionefficiency that can be attained using present concepts is estimated to be about 27-28 percent. To achieve conversionefficiencies above 30 percent using single-cell configurations it will be necessary to employ different concepts, such as spectral compression and broad-band detection. The implementation of these concepts would require major breakthroughs that are not anticipated in the near future.

The efficiency of ultrabroad-band wavelength conversion using orthogonal-pump four-wave mixing in a semiconductor optical amplifier is measured for the wavelength shifts from 1500 to 1640 nm. The variation of conversionefficiency is ＜ 0.9 dB over the wavelength range from 1530 to 1560 nm (C-band), and ＜ 4.5dB over the wavelength range from 1560 to 1610 nm (L-band). The maximum conversionefficiency is about -8.7 dB.

Full Text Available Mid-temperature thermoelectric conversionefficiencies of the IV-VI materials were calculated under the Boltzmann transport theory of carriers, taking the Seebeck, Peltier, and Thomson effects into account. The conversionefficiency was discussed with respect to the lattice thermal conductivity, keeping other parameters such as Seebeck coefficient and electrical conductivity to the same values. If room temperature lattice thermal conductivity is decreased up to 0.5W/mK, the conversionefficiency of a PbS based material becomes as high as 15% with the temperature difference of 500K between 800K and 300K.

Provskite-type catalysts, Ln0.6 Sr0.4 FexCo1-x O3 (Ln = Nd,Pr, Gd, Sm, La, 0＜x＜1) and Ln0.8Na0.2CoO3(Ln= La,Gd, Sm) were synthesized, their catalytic properties in the oxidative coupling of methane (OCM) were examined in a fixed-bed reactor. The former group presented higher activity in the OCM, but the main product was carbon dioxide. While the later group showed lower activity but much higher selectivity to C2 hydrocarbons compared with the former. Electrochemical measurements were conducted in a solid oxide membrane reactor with La0.8 Na0.2CoO3 as catalyst. The results showed that methane was oxidized to carbon dioxide and ethane by two parallel reactions. Ethane was oxidized to ethene and carbon dioxide. A fraction of ethene was oxidized deeply to carbon dioxide. The total selectivity to C2 hydrocarbons exceeded 70%. Based on the experimental results, a kinetic model was suggested to describe the reaction results.

In this work bifunctional (metal-acid) catalysts of Fe, Ni, Fe{sub 2}O{sub 3} and NiO over amorphous silica alumina support were characterized (acidity) and evaluated for the conversion of chloromethane in a fixed bed reactor. Temperature program tests TPD (Temperature Programmed Desorption) and TPR (Temperature Programmed Reduction) were performed to characterize the chemisorption sites for the impregnated and unimpregnated support. New adsorption sites were created on the metal supported catalysts. The conversion yield of chloromethane was evaluated for the five materials. The highest conversionconversion (85%) was observed for the unmodified support (SiAl) after 6 of reaction at 860 K and a WHSV (Weight Hourly Space Velocity) of 4,5 h{sup -1}. The best selectivity toward desirable hydrocarbons (C{sup 3}, C{sup 4}) was found for the Fe-SiAl catalyst. C{sup 3} was also found in the products stream when Ni/SiAl and NiO/SiAl catalysts were tested. Ni catalysts were the most favorable to methane production. The catalytic tests showed coke formation in all materials. For the SiAl support the desorption energy of chloromethane, determined by TPD runs, was 101,9 KJ/mol. The metals presented lower desorption energies (75,2 KJ/mol for Ni and 133,4 KJ/mol for Fe) than the oxides (190,1 KJ/mol for Fe{sub 2}O{sub 3} and 322,4 KJ/mol for NiO). (author)

This analysis characterizes century-scale trends in exergy efficiency in Japan. Exergy efficiency captures the degree to which energy inputs (such as coal) are converted into useful work (such as electricity or power to move a vehicle). This approach enables the estimation of net efficiencies which aggregate different technologies. Sectors specifically analyzed are electricity generation, transport, steel production, and residential space heating. One result is that the aggregate exergy efficiency of the Japanese economy declined slightly over the last half of the 20th century, reaching a high of around 38% in the late 1970s and falling to around 33% by 1998. The explanation for this is that while individual technologies improved dramatically over the century, less exergy-efficient ones were progressively adopted, yielding a net stabilization or decline. In the electricity sector, for instance, adoption of hydropower was followed by fossil-fired plants and then by nuclear power, each technology being successively less efficient from an exergy perspective. The underlying dynamic of this trend is analogous to declining ore grades in the mining sector. Increasing demand for exergy services requires expended utilization of resources from which it is more difficult to extract utility (e.g., falling water versus coal). We term this phenomenon efficiency dilution.

Methanol-to-hydrocarbons processes using HZSM-5 archetype acidic zeolites or zeotype SAPO-34 catalysts are regarded as a vital suite of conversion technologies to bypass petroleum-based routes for the production of specific fuels and petrochemical commodities. Special significance of the methanol chemistry originates from its versatility enabling selective transformations towards various products. Industry demonstrated successfully implementations of Methanol-To-Gasoline, Methanol-To-Olefin, and Methanol-To-Propylene processes, although the typical single-pass selectivity remained limited and recycling is necessary. Considerable fundamental research efforts both from experimental and computational sides contributed to unravel the underlying complex reaction mechanism. The indirect hydrocarbon pool mechanism, in which Broensted acid sites combined with adsorbed light olefins or lower methylbenzenes act as active centers, is generally accepted to explain the formation of light olefins. As olefin and aromatics populated catalytic sites show different reactivity in terms of activity and selectivity to ethylene or propylene, one could envision optimizing the product distribution by suitable co-feeding of specific hydrocarbons. The present work addresses three questions with an experimental study conducted under realistic MTP operation conditions: (1) How are ethylene and propylene formed at molecular level? (2) Which reaction pathway leads to the formation of undesired hydrogen transfer products? (3) Does olefin or aromatics co-feeding change the selectivity to ethylene or propylene? Xylenes and various olefins were co-fed with methanol to achieve a detailed understanding of the reaction mechanism over acidic HZSM-5 zeolites. Results suggest, that an olefin homologation/cracking route (olefin cycle) accounts for the autocatalytic (-like) nature and the majority of methanol consumption rather than the route involving aromatic intermediates (aromatics cycle). Co

.... With either low-temperature solution processing or vacuum evaporation, the overall conversionefficiencies of perovskite solar cells with organic hole-transporting material were quickly improved to over 15...

Feeding experiments were carried out with Metapenaeus monoceros using mangrove leaves at different stages of decomposition, in combination with rice bran. Maximum conversionefficiency was found in shrimps fed completely decomposed mangrove leaves...

Full Text Available Reactions associated with removal of oxygen from oxygenates (deoxygenation are an important aspect of hydrocarbon fuels production process from biorenewable substrates. Here we report the equilibrium composition of methanol-to-hydrocarbon system by minimizing the total Gibbs energy of the system using Cantera methodology. The system was treated as a mixture of 14 components which had CH3OH, C6H6, C7H8, C8H10 (ethyl benzene, C8H10 (xylenes, C2H4, C2H6, C3H6, CH4, H2O, C, CO2, CO, H2. The carbon in the equilibrium mixture was used as a measure of coke formation which causes deactivation of catalysts that are used in aromatization reaction(s. Equilibrium compositions of each species were analyzed for temperatures ranging from 300 to 1380 K and pressure at 0–15 atm gauge. It was observed that when the temperature increases the mole fractions of benzene, toluene, ethylbenzene, and xylene pass through a maximum around 1020 K. At 300 K the most abundant species in the system were CH4, CO2, and H2O with mole fractions 50%, 16.67%, and 33.33%, respectively. Similarly at high temperature (1380 K, the most abundant species in the system were H2 and CO with mole fractions 64.5% and 32.6% respectively. The pressure in the system shows a significant impact on the composition of species.

New type of syngas generator based on the partial conversion of natural gas (methane) or heavier hydrocarbons in volumetric permeable matrix burners in the conditions of locked infrared (IR) radiation is suggested as a high-productive, adaptable, and rather simple way of syngas and hydrogen production for various low-scale applications including enhancing the performance characteristics of power engines.

Buckling is one of the most common phenomena in atom-thick layered structures like graphene. While the buckling phenomenon usually causes disaster for most nanodevices, we illustrate one positive application of buckled graphene for energy harvest, storage and conversion. More specifically, we perform molecular dynamical simulations to show that buckled graphene can be used to collect wasted mechanical energy and store the energy in the form of internal knotting potential. Through strain engineering, the knotting potential can be converted into useful kinetic (thermal) energy that is highly concentrated at the free edges of buckled graphene. The present study demonstrates potential applications of buckled graphene for converting dispersed wasted mechanical energy into concentrated useful kinetic (thermal) energy.

Buckling is one of the most common phenomena in atom-thick layered structures like graphene. While the buckling phenomenon usually causes disaster for most nanodevices, we illustrate one positive application of buckled graphene for energy harvest, storage and conversion. More specifically, we perform molecular dynamical simulations to show that buckled graphene can be used to collect wasted mechanical energy and store the energy in the form of internal knotting potential. Through strain engineering, the knotting potential can be converted into useful kinetic (thermal) energy that is highly concentrated at the free edges of buckled graphene. The present study demonstrates potential applications of buckled graphene for converting dispersed wasted mechanical energy into concentrated useful kinetic (thermal) energy.

Full Text Available It was developed the technology of manufacturing planar betavoltaic converter based on silicon, providing a higher rate of conversion of ionizing radiation into electrical energy by reducing reverse currents. The active region of silicon p-i-n structure is 1 cm2, which is irradiated by the of radionuclide 63Ni with the activity 2,7 mCi/cm2. The results of experimental studies of C-V samples are presented. The values of the open-circuit voltage (Voc 0.111 V are presented and short circuit current density (Jsc 27 nA/cm2. The ma-ximum density of output power (Pmax was 1.52 nW/cm2.

Lignocellulosic biomass conversion to produce biofuels has received significant attention because of the quest for a replacement for fossil fuels. Among the various thermochemical and biochemical routes, fast pyrolysis followed by catalytic hydrotreating is considered to be a promising near-term opportunity. This paper reports on experimental methods used 1) at the National Renewable Energy Laboratory (NREL) for fast pyrolysis of lignocellulosic biomass to produce bio-oils in a fluidized-bed reactor and 2) at Pacific Northwest National Laboratory (PNNL) for catalytic hydrotreating of bio-oils in a two-stage, fixed-bed, continuous-flow catalytic reactor. The configurations of the reactor systems, the operating procedures, and the processing and analysis of feedstocks, bio-oils, and biofuels are described in detail in this paper. We also demonstrate hot-vapor filtration during fast pyrolysis to remove fine char particles and inorganic contaminants from bio-oil. Representative results showed successful conversion of biomass feedstocks to fuel-range hydrocarbon biofuels and, specifically, the effect of hot-vapor filtration on bio-oil production and upgrading. The protocols provided in this report could help to generate rigorous and reliable data for biomass pyrolysis and bio-oil hydrotreating research.

CNEEC’s mission has been to understand how nanostructuring of materials can enhance efficiency for solar energy conversion to produce hydrogen fuel and to solve fundamental cross-cutting problems. The overarching hypothesis underlying CNEEC research was that controlling, synthesizing and modifying materials at the nanometer scale increases the efficiency of energy conversion and storage devices and systems. In this pursuit, we emphasized the development of functional nanostructures that are based primarily on earth abundant and inexpensive materials.

We report on the experimental frequency conversion of a dim, coherent continuous-wave light field from 1550nm to 532nm with an external photon-number conversionefficiency of (84.4 +/- 1.5)%. We used sum-frequency generation, which was realized in a standing-wave cavity built around a periodically poled type I potassium titanyl phosphate (PPKTP) crystal, pumped by an intense field at 810 nm. Our result is in full agreement with a numerical model. For optimized cavity coupler reflectivities it predicts a conversionefficiency of up to 93% using the same PPKTP crystal.

Hierarchically porous zeolite Beta (Beta-MS) synthesized by a soft-templating method contains remarkable intra-crystalline mesoporosity, which reduces the diffusion length in zeolite channels down to several nanometers and alters the distribution of Al among distinct crystallographic sites. When used as a catalyst for the conversion of methanol to hydrocarbons (MTH) at 330 oC, Beta-MS exhibited a 2.7-fold larger conversion capacity, a 2.0-fold faster reaction rate, and a remarkably longer lifetime than conventional zeolite Beta (Beta-C). The superior catalytic performance of Beta-MS is attributed to its hierarchical structure, which offers full accessibility to all catalytic active sites. In contrast, Beta-C was easily deactivated because a layer of coke quickly deposited on the outer surfaces of the catalyst crystals, impeding access to interior active sites. This difference is clearly demonstrated by using electron microscopy combined with electron energy loss spectroscopy to probe the distribution of coke in the deactivated catalysts. At both low and high conversions, ranging from 20% to 100%, Beta-MS gave higher selectivity towards higher aliphatics (C4-C7) but lower ethene selectivity compared to Beta-C. Therefore, we conclude that a hierarchical structure decreases the residence time of methylbenzenes in zeolite micropores, disfavoring the propagation of the aromatic-based catalytic cycle. This conclusion is consistent with a recent report on ZSM-5 and is also strongly supported by our analysis of soluble coke species residing in the catalysts. Moreover, we identified an oxygen-containing compound, 4-methyl-benzaldehyde, in the coke, which has not been observed in the MTH reaction before.

We describe the elaboration of a multiscale-tailored bioelectrocatalytic system. The combination of two enzymes, D-sorbitol dehydrogenase and diaphorase, is studied with respect to the oxidation of D-sorbitol as a model system. The biomolecules are immobilized in an electrodeposited paint (EDP) layer. Reproducible and efficient catalysis of D-sorbitol oxidation is recorded when this system is immobilized on a gold electrode modified by a self-assembled monolayer of 4-carboxy-(2,5,7-trinitro-9-fluorenylidene)malonitrile used as a mediator. The insertion of mediator-modified gold nanoparticles into the EDP film increases significantly the active surface area for the catalytic reaction, which can be further enhanced when the whole system is immobilized in macroporous gold electrodes. This multiscale architecture finally leads to a catalytic device with optimized efficiency for potential use in biosensors, bioelectrosynthesis, and biofuel cells.

Selective cleavage of C-O-C bonds in lignin without disrupting C-C linkages can result in releasing aromatic monomers and dimers that can be subsequently converted into chemicals and fuels. Results showed that both biomass-derived lignin and lignin model compounds were depolymerized in a highly concentrated ZnCl2 solution. Zn2+ ions in highly concentrated ZnCl2 solutions appeared to selectively coordinate with C-O-C bonds to cause key linkages of lignin much easier to cleave. In 63 wt.% ZnCl2 solution at 200 °C for 6 h, nearly half of the softwood technical lignin was converted to liquid products, of which the majority was alkylphenols. Results indicated that most β-O-4 and Cmethyl-OAr bonds of model compounds were cleaved undersame conditions, providing a foundation towards understanding lignin depolymerization in a concentrated ZnCl2 solution. The phenolic products were further converted into cyclic hydrocarbons via hydrodeoxygenation and coupling reactions by co-catalyst Ru/C.

An analytical framework is presented that permits examination of the limit to the efficiency of various solar power conversion devices. Thermodynamic limits to solar power efficiency are determined for both quantum and thermal systems, and the results are applied to a variety of devices currently considered for use in space systems. The power conversionefficiency for single-threshold energy quantum systems receiving unconcentrated air mass zero solar radiation is limited to 31 percent. This limit applies to photovoltaic cells directly converting solar radiation, or indirectly, as in the case of a thermophotovoltaic system. Photoelectrochemical cells rely on an additional chemical reaction at the semiconductor-electrolyte interface, which introduces additional second-law demands and a reduction of the solar conversionefficiency. Photochemical systems exhibit even lower possible efficiencies because of their relatively narrow absorption bands. Solar-powered thermal engines in contact with an ambient reservoir at 300 K and operating at maximum power have a peak conversionefficiency of 64 percent, and this occurs for a thermal reservoir at a temperature of 2900 K. The power conversionefficiency of a solar-powered liquid metal magnetohydrodydnamic generator, a solar-powered steam turbine electric generator, and an alkali metal thermoelectric converter is discussed.

The U.S. Department of Energy promotes the production of liquid fuels from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass sustainable supply, logistics, conversion, and overall system sustainability. As part of its involvement in this program, Idaho National Laboratory (INL) investigates the feedstock logistics economics and sustainability of these fuels. Between 2000 and 2012, INL quantified and the economics and sustainability of moving biomass from the field or stand to the throat of the conversion process using conventional equipment and processes. All previous work to 2012 was designed to improve the efficiency and decrease costs under conventional supply systems. The 2012 programmatic target was to demonstrate a biomass logistics cost of $55/dry Ton for woody biomass delivered to fast pyrolysis conversion facility. The goal was achieved by applying field and process demonstration unit-scale data from harvest, collection, storage, preprocessing, handling, and transportation operations into INL’s biomass logistics model.

The goal of this work was aimed to improve the power conversionefficiency of single crystalline silicon-based photovoltaic cells by using the solar spectral conversion principle,which employs an up-conversion phosphor to convert a low energy infrared photon to the more energetic visible photons to improve the spectral response.In this study,the surface of multicrystalline silicon solar cells was coated with an up-conversion molybdate phosphor to improve the spectral response of the solar cell in the ncar-infiared spectral range.The short circuit current (Isc),open circuit voltage (Voc),and conversionefficiency (η) of spectral conversion cells were measured.Preliminary experimental results revealed that the light conversionefficiency of a 1.5％-2.7％ increase in Si-based cell was achieved.

The problem of HE mass gain minimization is extremely important due to environmental and safety considerations of MCG application to mobile simulators of lightning current (MSLC). There are several methods of increasing the efficiency of MSLC with an electrical explosive opening switch (EEOS) in the circuit of the secondary winding of a conventional transformer (CT) with inductance L2. One may use the battery of fast-run MCGs of a small diameter, or increase both the magnitude of L2 and the energy of power supply bank of capacitors, or use larger diameter wires with solid insulation. Results of experiments using spiral-coaxial MCG, 36 mm in diameter, have produced an acceptable efficiency of 12%. When the wires were insulated with polyethylene, energy absorption was high. Analysis of alternatives to open switches (OS) in the MCG circuit has shown their competitiveness. They allow reduction of the optimum L2 magnitude, use of a modular device design, and shaping of the waveform and of the lightning current pulse duration during its droop by introducing one additional MCG module into the circuit.

Converting low-frequency electrical signals into much higher frequency optical signals has enabled modern communications networks to leverage both the strengths of microfabricated electrical circuits and optical fiber transmission, allowing information networks to grow in size and complexity. A microwave-to-optical converter in a quantum information network could provide similar gains by linking quantum processors via low-loss optical fibers and enabling a large-scale quantum network. However, no current technology can convert low-frequency microwave signals into high-frequency optical signals while preserving their fragile quantum state. For this demanding application, a converter must provide a near-unitary transformation between different frequencies; that is, the ideal transformation is reversible, coherent, and lossless. Here we demonstrate a converter that reversibly, coherently, and efficiently links the microwave and optical portions of the electromagnetic spectrum. We use our converter to transfer cl...

Link failures in wide area networks are common and cause significant data losses. Mesh-based protection schemes offer high capacity efficiency but they are slow and require complex signaling. Additionally, real-time reconfiguration of a cross-connect threatens their transmission integrity. On the other hand, coding-based protection schemes are proactive. Therefore, they have higher restoration speed, lower signaling complexity, and higher transmission integrity. This paper introduces a coding-based protection scheme, named Coded Path Protection (CPP). In CPP, a backup copy of the primary data is encoded with other data streams, resulting in capacity savings. This paper presents an optimal and simple capacity placement and coding group formation algorithm. The algorithm converts the sharing structure of any solution of a Shared Path Protection (SPP) technique into a coding structure with minimum extra capacity. We conducted quantitative and qualitative comparisons of our technique with the SPP and, another tec...

A simple modification of Pauly's model for relating food conversionefficiency (K sub(1)) and body weight is proposed. The key parameter is an index to how efficiently food can be absorbed; the other parameter is related to the surface-limiting growth, an important component of von Bertalanff's and Pauly's theories of fish growth.

@@ The world has an abundant supply of low cost natural gas in remote locations. The monetization of these stranded gas resources requires new technologies and markets. GTP (Gas To Products ) technologies emerge as options to efficiently convert this resource into clean, high value fuels and chemicals.

The performance of nano-scale energy conversion devices is studied in the framework of state-space models where a device is described by a graph comprising states and transitions between them represented by nodes and links, respectively. Particular segments of this network represent input (driving) and output processes whose properly chosen flux ratio provides the energy conversionefficiency. Simple cyclical graphs yield Carnot efficiency for the maximum conversion yield. We give general proof that opening a link that separate between the two driving segments always leads to reduced efficiency. We illustrate these general result with simple models of a thermoelectric nanodevice and an organic photovoltaic cell. In the latter an intersecting link of the above type corresponds to non-radiative carriers recombination and the reduced maximum efficiency is manifested as a smaller open-circuit voltage.

The performance of nano-scale energy conversion devices is studied in the framework of state-space models where a device is described by a graph comprising states and transitions between them represented by nodes and links, respectively. Particular segments of this network represent input (driving) and output processes whose properly chosen flux ratio provides the energy conversionefficiency. Simple cyclical graphs yield Carnot efficiency for the maximum conversion yield. We give general proof that opening a link that separate between the two driving segments always leads to reduced efficiency. We illustrate these general result with simple models of a thermoelectric nanodevice and an organic photovoltaic cell. In the latter an intersecting link of the above type corresponds to non-radiative carriers recombination and the reduced maximum efficiency is manifested as a smaller open-circuit voltage.

The research project 'Energy efficient selective reforming of hydrocarbons', funded by the Swedish and Energinet.dk Agency has now reached its end. The report is an overview of the work. Details of the work within the different areas can be found in the reports from each part. In this project, an innovative method for tar removal and reformation of hydrocarbons was investigated: Chemical Looping Reforming (CLR). This gas treatment has the potential to be economically competitive, reliable and environmentally friendly (due to higher energy efficiency, amongst others). The aim of the CLR is to 1) eliminate downstream problems with tar 2) simplify the energy recovery from the hot product gas 3) selectively save lighter hydrocarbons for the production of synthetic natural gas (SNG). A guarantor for the outcome of the project is the engagement of Goeteborg Energi, which has a commitment to build a 20 MW output SNG plant by 2012. DTU (Danish Technical University) is responsible for carrying out the laboratorial part, where different oxygen carriers for the CLR have been considering their capability of selectively reforming hydrocarbons. The conclusion was that, of the four carriers tested, the Mn and Ni40 was the most promising. CUT (Chalmers University of Technology) has installed a 600 W CLR unit connected to a slipstream from the gasifier. During the firing season 2010 the CLR has been tested with raw gas for 36 hours and the results so far show that the equipment works as intended and that it can reduce the amount of tars substantially. GE (Goeteborg Energi AB) together with SEP (Scandinavian Energy Project AB) and CUT have studied the integration of a methane production plant to an existing boiler. The main focus of the study has been the gasifier and the CLR. The integration of a 100 MW methane production plant is estimated to cost 1.3-2.4 billion SEK. The different work packages have altogether shown that a CLR is a possible solution to the tar problem

The Earth receives around 1000 W.m(-2) of power from the Sun and only a fraction of this light energy is able to be converted to biomass (chemical energy) via the process of photosynthesis. Out of all photosynthetic organisms, microalgae, due to their fast growth rates and their ability to grow on non-arable land using saline water, have been identified as potential source of raw material for chemical energy production. Electrical energy can also be produced from this same solar resource via the use of photovoltaic modules. In this work we propose a novel method of combining both of these energy production processes to make full utilisation of the solar spectrum and increase the productivity of light-limited microalgae systems. These two methods of energy production would appear to compete for use of the same energy resource (sunlight) to produce either chemical or electrical energy. However, some groups of microalgae (i.e. Chlorophyta) only require the blue and red portions of the spectrum whereas photovoltaic devices can absorb strongly over the full range of visible light. This suggests that a combination of the two energy production systems would allow for a full utilization of the solar spectrum allowing both the production of chemical and electrical energy from the one facility making efficient use of available land and solar energy. In this work we propose to introduce a filter above the algae culture to modify the spectrum of light received by the algae and redirect parts of the spectrum to generate electricity. The electrical energy generated by this approach can then be directed to running ancillary systems or producing extra illumination for the growth of microalgae. We have modelled an approach whereby the productivity of light-limited microalgae systems can be improved by at least 4% through using an LED array to increase the total amount of illumination on the microalgae culture.

Linking classical microwave electrical circuits to the optical telecommunication band is at the core of modern communication. Future quantum information networks will require coherent microwave-to-optical conversion to link electronic quantum processors and memories via low-loss optical telecommunication networks. Efficientconversion can be achieved with electro-optical modulators operating at the single microwave photon level. In the standard electro-optic modulation scheme this is impossible because both, up- and downconverted, sidebands are necessarily present. Here we demonstrate true single sideband up- or downconversion in a triply resonant whispering gallery mode resonator by explicitly addressing modes with asymmetric free spectral range. Compared to previous experiments, we show a three orders of magnitude improvement of the electro-optical conversionefficiency reaching 0.1% photon number conversion for a 10GHz microwave tone at 0.42mW of optical pump power. The presented scheme is fully compatible...

Full Text Available The determination of retention efficiencies of halogenated and non-halogenated hydrocarbon in selected wetland ecosystems in Lake Victoria basin was carried out. Qualitative and quantitative determination of the presence of residual hydrocarbons in Kigwal/Kimondi, Nyando and Nzoia wetland ecosystems using Gas Chromatography - Mass Spectrometer (GC-MS instrument indicated the presence of residual organochlorines, organophosphorus, carbamates and synthetic pyrethroid hydrocarbons in water, sediment and plant materials. In order to compare the retention efficiencies of the wetlands, the wetland ecosystems were divided into three different sections, namely: inlet, mid and outlet. Calculations of mass balances of residual halogenated and non-halogenated hydrocarbons at the respective sections was done taking into account the partition of the studied compounds in samples of water, sediments and papyrus reed plant materials and analyzed using validated Gas Chromatography - Mass Spectrometer (GC-MS method. From the analysis, several residual hydrocarbons namely: bendiocarb, benzene hexachloride (BHC, carbaryl, cypermethrin, decis, deltamethrin, diazinon, dieldrin, DDT, DDD, DDE, malathion, propoxur, sumithion, 5-phenylrhodanine, 1,3,5-trichlorobenzene, 1-(2-phenoxybenzylhydrazine were detected and quantified. The levels of the selected residual hydrocarbons in water samples were used to calculate the retention efficiencies of a specific hydrocarbon and the values recorded. Generally, River Nyando wetland recorded mean percentage retention efficiencies of 76 and 94% for dry and rainy seasons respectively; Kigwal/Kimondi wetland had seasonal mean percentage retention efficiencies of 63 to 78%. River Nzoia also had calculated seasonal mean percentage retention efficiencies of between 56 to 88%. Dry season had lower mean percentages retention efficiencies as compared to rainy season in the three wetlands of interest during the period of study. The study

Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1500 K. Depending on the nature of parasitic losses, overall thermal-to-electric conversionefficiencies greater than 20 percent are feasible.

Optical frequency conversion has applications ranging from tunable light sources to telecommunications-band interfaces for quantum information science. Here, we demonstrate efficient, low-noise frequency conversion on a nanophotonic chip through four-wave-mixing Bragg scattering in compact (footprint 60% for the last two processes, a signal conversion bandwidth of >1 GHz, a required continuous-wave pump power of equations and the Lugiato-Lefever equation are used to model device performance, and show quantitative agreement with measurements.

Energy-intensive chemical conversion of crude algal oils into biodiesel is a major barrier for cost-effective algal biofuel production. To overcome this problem, we developed an enzyme-based platform for conversion of crude algal oils into fatty acid methyl esters. Crude algal oils were extracted from the oleaginous microalga Nannochloropsis oceanica IMET1 and converted by an immobilized lipase from Candida antarctica. The effects of different acyl acceptors, t-butanol as a co-solvent, oil to t-butanol ratio, oil to methanol ratio, temperature and reaction time on biodiesel conversionefficiency were studied. The conversionefficiency reached 99.1% when the conversion conditions were optimized, i.e., an oil to t-butanol weight ratio of 1:1, an oil to methanol molar ratio of 1:12, and a reaction time of 4h at 25°C. The enzymatic conversion process developed in this study may hold a promise for low energy consumption, low wastewater-discharge biochemical conversion of algal feedstocks into biofuels.

Metasurfaces have powerful abilities to manipulate the properties of electromagnetic waves flexibly, especially the modulation of polarization state for both linearly polarized (LP) and circularly polarized (CP) waves. However, the transmission efficiency of cross-polarization conversion by a single-layer metasurface has a low theoretical upper limit of 25% and the bandwidth is usually narrow, which cannot be resolved by their simple additions. Here, we efficiently manipulate polarization coupling in multilayer metasurface to promote the transmission of cross-polarization by Fabry-Perot resonance, so that a high conversion coefficient of 80–90% of CP wave is achieved within a broad bandwidth in the metasurface with C-shaped scatters by theoretical calculation, numerical simulation and experiments. Further, fully controlling Pancharatnam-Berry phase enables to realize polarized beam splitter, which is demonstrated to produce abnormal transmission with high conversionefficiency and broad bandwidth. PMID:27703254

Clique sizes for chimpanzee (Pan troglodytes) grooming and for human conversation are compared in order to test Robin Dunbar's hypothesis that human language is almost three times as efficient a bonding mechanism as primate grooming. Recalculation of the data provided by Dunbar et al. (1995) reveals that the average clique size for human conversation is 2.72 whereas that of chimpanzee grooming is shown to be 2.18. The efficiency of human conversation and actual chimpanzee grooming over Dunbar's primate grooming model (always one-to-one and a one-way interaction) is 1.27 and 1.25, respectively, when we take role alternation into account. Chimpanzees can obtain about the same efficiency as humans in terms of quantity of social interactions because their grooming is often mutual and polyadic.

Full Text Available n-type ZnO:Cu photoanodes were fabricated by simple spray pyrolysis deposition technique. Influence of low concentration (range ~10−4–10−1% of Cu doping in hexagonal ZnO lattice on its photoelectrochemical performance has been investigated. The doped photoanodes displayed 7-time enhanced conversionefficiencies with respect to their undoped counterpart, as estimated from the photocurrents generated under simulated solar radiation. This is the highest enhancement in the solar conversionefficiency reported so far for the Cu-doped ZnO. This performance is attributed to the red shift in the band gap of the Cu-doped films and is in accordance with the incident-photon-current-conversionefficiency (IPCE measurements. Electrochemical studies reveal an n-type nature of these photoanodes. Thus, the study indicates a high potential of doped ZnO films for solar energy applications, in purview of the development of simple nanostructuring methodologies.

Based on a Type Ⅱ non-critically phase-matched KTA crystal,a low-threshold and high conversionefficiency midinfrared optical parametric oscillator(OPO)pumped by a diode-end-pumped Nd:YVO_4 laser is demonstrated.The OPO threshold is only 0.825 W.The maximum output power of 435mW at 3.47μm is achieved with the repetition rate of 30kHz,corresponding to an optical-to-optical conversionefficiency of 4.4%.The photon conversionefficiency is as high as about 64%.The pulse width is 3.5 ns with a peak power of 4 kW for the maximum output power.

We propose and demonstrate semiconductor nanocrystal based photovoltaic scintillators integrated on solar cells to enhance photovoltaic device parameters including spectral responsivity, open circuit voltage, short circuit current, fill factor, and solar conversionefficiency in the ultraviolet. Hybridizing (CdSe)ZnS core-shell quantum dots of 2.4 nm in diameter on multi-crystalline Si solar cells for the first time, we show that the solar conversionefficiency is enhanced 2 folds under white light illumination similar to the solar spectrum. Such nanocrystal scintillators provide the ability to extend the photovoltaic activity towards UV.

Full Text Available A novel Vivaldi rectenna operated at 35 GHz with high millimeter wave to direct current (MMW-to-DC conversionefficiency is presented and the arrays are investigated. The measured conversionefficiency is 51.6% at 35 GHz and the efficiency higher than 30% is from 33.2 GHz to 36.6 GHz when the input MMW power is 79.4 mW. The receiving Vivaldi antenna loaded with metamaterial units has a high gain of 10.4 dBi at 35 GHz. A SIW- (substrate integrated waveguide- to-microstrip transition is designed not only to integrate the antenna with the rectifying circuit directly but also to provide the DC bypass for the rectifying circuit. When the power density is 8.7 mW/cm2, the received MMW power of the antenna is 5.6 mW, and the maximum conversionefficiency of the rectenna element is 31.5%. The output DC voltage of the element is nearly the same as that of the parallel array and is about half of the series array. The DC power obtained by the 1 × 2 rectenna arrays is about two times as much as that of the element. The conversionefficiencies of the arrays are very close to that of the element. Large scale arrays could be expended for collecting more DC power.

Full Text Available Bio-gasification is a new technology and considered as a more efficient way to utilize bio-energy. The economic feasibility becomes one of the greatest issues when we apply this new technology. Evaluation of economic feasibility of a bio-gasification facility needs better understanding of its production unit cost under different capacities and different working shift modes. The objective of this study was to evaluate the unit cost of biofuel products (Liquid HCs, Light HCs and Oxygenates CxHyOz under different capacities using a modeling method. The cost analysis model was developed using Visual Basic Microsoft 2008, computer programming language and mathematical equations. The modeling results showed that the unit costs of biofuel product from bio-gasification facility were significantly affected by production capacities of facilities. As the facility capacity increased from 65 to 10,000 N m3 h−1, the biofuel production unit cost of gas (Light HCs, oil (Liquid HCs, and aqueous (Oxygenates CxHyOz decreased from $38.92 per MMBTU, $30.89 per gallon and $25.74 per gallon to $2.01 per MMBTU, $1.59 per gallon, and $1.33 per gallon, respectively. The results of the sensitivity analysis showed that feedstock cost was the most sensitive cost factor on unit costs for all biofuel products at high capacity. The cost analysis model developed in this study could be used to optimize production unit costs of bio-fuel products from bio-gasification facility.

Optical frequency conversion has applications ranging from tunable light sources to telecommunications-band interfaces for quantum information science. Here, we demonstrate efficient, low-noise frequency conversion on a nanophotonic chip through four-wave-mixing Bragg scattering in compact (footprint 60 % for the last two processes, a signal conversion bandwidth > 1 GHz, < 60 mW of continuous-wave pump power needed, and background noise levels between a few fW and a few pW, these devices are suitable for quantum frequency conversion of single photon states from InAs quantum dots. Simulations based on coupled mode equations and the Lugiato-Lefever equation are used to model device performance, and show quantitative agreement with measurements.

Conversionefficiency enhancement techniques have been demonstrated for quasi-phase matched (QPM) second-harmonic generation (SHG). First, a technique is described for confining the high fundamental optical power density in a waveguide with a domain-inverted grating (SHG waveguide) (i.e., a technique for monolithic integration), the SHG waveguide, and a distributed Bragg reflector (DBR). A 40-percent increase in the conversion compared with a conventional device without a DBR was achieved under QPM conditions. Also described is a method of automatically satisfying QPM conditions, using a laser diode (LD) with antireflection-coated facets. The InP/InGaAsP LDs were used and it was confirmed that the LD oscillated at a wavelength satisfying the QPM conditions. The normalized conversionefficiency was 4.1 percent/W per sq cm.

stages, three paralleled DC/DC converters are implemented. A Genetic Algorithm performs the on-line optimization of the DC network’s global efficiency, generating the optimal current sharing ratios of the concurrent power converters. The overall DC/DC conversion system including the optimization section...... for, such as: components loss parameters, components ageing, load currents, switching frequency and input voltage. Simulation results considering several case studies are presented and the benefits brought by the optimization algorithm in terms of power saving are widely discussed for each case study.......In this paper, an on-line management system for the optimal efficiency operation of a multi-bus DC home distribution system is proposed. The operation of the system is discussed with reference to a distribution system with two conversion stages and three voltage levels. In each of the conversion...

Full Text Available We analyse the process of conversion of near-field thermal radiation into usable work by considering the radiation emitted between two planar sources supporting surface phonon-polaritons. The maximum work flux that can be extracted from the radiation is obtained taking into account that the spectral flux of modes is mainly dominated by these surface modes. The thermodynamic efficiencies are discussed and an upper bound for the first law efficiency is obtained for this process.

Full Text Available Modern trends in development of aircraft engineering go with development of vehicles of the fifth generation. The features of aircrafts of the fifth generation are motivation to use new high-performance systems of onboard power supply. The operating temperature of the outer walls of engines is of 800–1000 K. This corresponds to radiation heat flux of 10 kW/m2 . The thermal energy including radiation of the engine wall may potentially be converted into electricity. The main objective of this paper is to analyze if it is possible to use a high efficiency thermoelectric conversion of heat into electricity. The paper considers issues such as working processes, choice of materials, and optimization of thermoelectric conversion. It presents the analysis results of operating conditions of thermoelectric generator (TEG used in advanced hightemperature power devices. A high-temperature heat source is a favorable factor for the thermoelectric conversion of heat. It is shown that for existing thermoelectric materials a theoretical conversionefficiency can reach the level of 15–20% at temperatures up to 1500 K and available values of Ioffe parameter being ZT = 2–3 (Z is figure of merit, T is temperature. To ensure temperature regime and high efficiency thermoelectric conversion simultaneously it is necessary to have a certain match between TEG power, temperature of hot and cold surfaces, and heat transfer coefficient of the cooling system. The paper discusses a concept of radiation absorber on the TEG hot surface. The analysis has demonstrated a number of potentialities for highly efficientconversion through using the TEG in high-temperature power devices. This work has been implemented under support of the Ministry of Education and Science of the Russian Federation; project No. 1145 (the programme “Organization of Research Engineering Activities”.

In the high power solid laser driver, the frequency conversion unit is of strict requirement to meet the drive condition of ICF. The performance of large caliber KDP crystal, which is the core of frequency conversion of laser, is a vital aspect affecting the overall technical index of the laser driver. In order to get a higher efficiency of frequency conversion, KDP crystal must keep a better surface condition, which asks for high-quality assemblage and adjustment. The current method used in engineering has insufficient knowledge and recognition on surface deformation control of the crystal. Meanwhile, the method itself is of low efficiency on clamping, and lacks of protection for the crystal. Thus, in this article an investigation of crystal clamping method with lower force was performed, factors affecting the surface of crystal were explored, through both imitation and experiment. The clamping method was redesigned and the frequency conversionefficiency was tested. Meanwhile, with the new method, clamping efficiency increases, the optical performance of crystals improves, and the crystals get better protection.

This paper theoretically investigates the effect of end reflections on the operation of the coaxial relativistic backward wave oscillator (CRBWO). It is found that the considerable enhancement of the end reflection at one end increases the conversionefficiency, but excessively large end reflections at both ends weaken the asynchronous wave-beam interaction and thus reduce the conversionefficiency. Perfect reflection at the post end significantly improves the interaction between the electron beam and the asynchronous harmonic so that the conversionefficiency is notably increased. Based on the theoretical research, the diffraction-CRBWO with the generated microwave diffracted and output through the front end of the coaxial slow wave structure cavity is proposed. The post end is conductively closed to provide the perfect reflection. This promotes the amplitude and uniformity of the longitudinal electric field on the beam transmission line and improves the asynchronous wave-beam interaction. In numerical simulations under the diode voltage and current of 450 kV and 5.84 kA, microwave generation with the power of 1.45 GW and the conversionefficiency of 55% are obtained at the frequency of 7.45 GHz.

We report on the further development of the statistical approach to determine the conversionefficiency of implanted ions into emitting centers and present the measurement method based on the confocal micro-luminescence mapping. It involves the micro-luminescence mapping with a narrow-open confocal aperture, followed by the statistical analysis of the photoluminescence signal from an ensemble of emitting centers. The confocal mapping method has two important advantages compared to the recently discussed aperture-free method (J. Lumin. 131 (2011) 489): it is less sensitive to errors in the laser spot size and has a well defined useful area. The confocal mapping has been applied to the Xe center in diamond. The conversionefficiency has been found to be about 0.28, which is in good agreement with the results of the aperture-free method. - Highlights: Black-Right-Pointing-Pointer Conversionefficiency of implanted ions into emitting centers - statistical approach. Black-Right-Pointing-Pointer Micro-luminescence mapping with open and narrow confocal aperture - comparison. Black-Right-Pointing-Pointer Advantages of the confocal micro-luminescence mapping. Black-Right-Pointing-Pointer Confocal micro-luminescence mapping has been applied to the Xe center in diamond. Black-Right-Pointing-Pointer The conversionefficiency has been found to be about 0.28.

of prey. Here we studied zooplankton consumption and energy conversionefficiency of lesser sandeel (Ammodytes marinus) in the central North Sea, using stomach data, length and weight-at-age data, bioenergetics, and hydrodynamic modeling. The results suggested: (i) Lesser sandeel in the Dogger area depend...... sandeel densities and growth rates per area than larger habitats...

This paper theoretically investigates the effect of end reflections on the operation of the coaxial relativistic backward wave oscillator (CRBWO). It is found that the considerable enhancement of the end reflection at one end increases the conversionefficiency, but excessively large end reflections at both ends weaken the asynchronous wave-beam interaction and thus reduce the conversionefficiency. Perfect reflection at the post end significantly improves the interaction between the electron beam and the asynchronous harmonic so that the conversionefficiency is notably increased. Based on the theoretical research, the diffraction-CRBWO with the generated microwave diffracted and output through the front end of the coaxial slow wave structure cavity is proposed. The post end is conductively closed to provide the perfect reflection. This promotes the amplitude and uniformity of the longitudinal electric field on the beam transmission line and improves the asynchronous wave-beam interaction. In numerical simulations under the diode voltage and current of 450 kV and 5.84 kA, microwave generation with the power of 1.45 GW and the conversionefficiency of 55% are obtained at the frequency of 7.45 GHz.

We report conversionefficiencies of experimental single and dual lightguide luminescent solar concentrators. We have built several 5x5cm2 and 10x10 cm2 LSC demonstrators, consisting of c-Si photovoltaiccells attached to luminescent lightguides of Lumogen F Red 305 dyeand perylene perinone dye. The

Ramp-up experiments by means of lower hybrid wave on HT-7 superconducting tokamak have been performed and analyzed. A ramp-up rate of over 300 kA/s is obtained and a conversionefficiency of over 10% has been achieved during the ramp-up phase. The study of the dependence of conversionefficiency on plasma density shows that the conversionefficiency is affected by the driven current, which is mainly dominated by the competition of impurity concentration with wave accessibility condition. In addition, the effect of current profile may play an important role in determining the conversionefficiency.

Ramp-up experiments by means of lower hydrid wave on HT-7 superconducting tokamak have been performed and analyzed.A ramp-up rate of over 300kA/s is obtained and a conversionefficiency of over 10% has been achieved during the ramp-up phases.The study of the dependence of conversionefficiency on plasma density shows that the conversionefficiency is affected by the driven current,which is mainly dominated by the competition of impurity concentration with wave accessibility condition.In addition,the effect of current profile may play an important role in determining the conversionefficiency.

The efficient production of syngas from a CH{sub 4}+CO{sub 2} mixture in an atmospheric pulsed glow discharge, sustained by corona pre-ionization, has been investigated. The products were mainly syngas (CO, H{sub 2}) and hydrocarbons up to C{sub 4}, with acetylene having the highest selectivity. The energy efficiency was within 15-40% for different experimental conditions, which demonstrates a comprehensive improvement relative to the achievements of other types of non-equilibrium plasma. These values are, however, comparable with the efficiencies obtained by gliding arc plasmas but this plasma operates at near room temperature. Furthermore, it has been shown that the energy efficiency is increased by decreasing the effective residence time. The effects of molar ratio CH{sub 4} : CO{sub 2}, voltage, repetition rate and gas flow rate on conversion, energy efficiencies and the selectivities have also been investigated. The higher efficiency obtained in this kind of plasma is discussed and attributed to the short pulse regime and electric field uniformity.

CO2 conversion into value-added products has gained significant interest over the few last years, as the greenhouse gas concentrations constantly increase due to anthropogenic activities. Here we report on experiments for CO2 conversion by means of a cold atmospheric plasma using a cylindrical flowing dielectric barrier discharge (DBD) reactor. A detailed comparison of this DBD ignited in a so-called burst mode (i.e. where an AC voltage is applied during a limited amount of time) and pure AC mode is carried out to evaluate their effect on the conversion of CO2 as well as on the energy efficiency. Decreasing the duty cycle in the burst mode from 100% (i.e. corresponding to pure AC mode) to 40% leads to a rise in the conversion from 16--26% and to a rise in the energy efficiency from 15 to 23%. Based on a detailed electrical analysis, we show that the conversion correlates with the features of the microfilaments. Moreover, the root-mean-square voltage in the burst mode remains constant as a function of the proc...

CO2 conversion into value-added products has gained significant interest over the few last years, as the greenhouse gas concentrations constantly increase due to anthropogenic activities. Here we report on experiments for CO2 conversion by means of a cold atmospheric plasma using a cylindrical flowing dielectric barrier discharge (DBD) reactor. A detailed comparison of this DBD ignited in a so-called burst mode (i.e. where an AC voltage is applied during a limited amount of time) and pure AC mode is carried out to evaluate their effect on the conversion of CO2 as well as on the energy efficiency. Decreasing the duty cycle in the burst mode from 100% (i.e. corresponding to pure AC mode) to 40% leads to a rise in the conversion from 16-26% and to a rise in the energy efficiency from 15 to 23%. Based on a detailed electrical analysis, we show that the conversion correlates with the features of the microfilaments. Moreover, the root-mean-square voltage in the burst mode remains constant as a function of the process time for the duty cycles <70%, while a higher duty cycle or the usual pure AC mode leads to a clear voltage decay by more than 500 V, over approximately 90 s, before reaching a steady state regime. The higher plasma voltage in the burst mode yields a higher electric field. This causes the increasing the electron energy, and therefore their involvement in the CO2 dissociation process, which is an additional explanation for the higher CO2 conversion and energy efficiency in the burst mode.

Full Text Available Present-day Small Hydropower Plants (SHPs have a large development potential because of the increasing interest in renewable resources and distributed energy generation. However, the variable hydrological conditions that are found in the run-of-the-river projects require operations over a wide range of water flow and head variations. Special control methods and system topologies are needed to maintain the high efficiency of energy conversion systems. The synchronous generator excited by permanent magnets (PMSG characterizes higher and more stable efficiency characteristic, in relation to the generated power, then mostly used in SHPs asynchronous machine. This paper investigates the efficiency of an example SHP solution. The researched system is based on an innovative generation unit (hydro-set containing a propeller turbine integrated with the PMSG. In order to obtain the high efficiency in a wide range of water flow the variable speed operation method has been used. This solution requires a Power Electronic Unit in the energy conversion system to match the load and control the power flow from the generator to the grid. Efficiency analysis concerns all elements of the energy conversion system. Presented results comes from the real SHP of 150kW nominal power.

An effective way to improve the power conversionefficiency of organic solar cells is to use a tandem architecture consisting of two subcells, so that a broader part of the solar spectrum can be used and the thermalization loss of photon energy can be minimized. For a tandem cell to work well, it is important for the subcells to have complementary absorption characteristics and generate high and balanced (matched) currents. This requires a rather challenging effort to design and select suitable active materials for use in the subcells. Here, we report a high-performance solution-processed, tandem solar cell based on the small molecules DR3TSBDT and DPPEZnP-TBO, which offer efficient, complementary absorption when used as electron donor materials in the front and rear subcells, respectively. Optimized devices achieve a power conversionefficiency of 12.50% (verified 12.70%), which represents a new level of capability for solution-processed, organic solar cells.

The increase in efficiency of RF power generation for future large accelerators is considered a high priority issue. The vast majority of the existing commercial high-power RF klystrons operates in the electronic efficiency range between 40% and 55%. Only a few klystrons available on the market are capable of operating with 65% efficiency or above. In this paper, a new method to achieve 90% RF power conversionefficiency in a klystron amplifier is presented. The essential part of this method is a new bunching technique - bunching with bunch core oscillations. Computer simulations confirm that the RF production efficiency above 90% can be reached with this new bunching method. The results of a preliminary study of an L-band, 20-MW peak RF power multibeam klystron for Compact Linear Collider with the efficiency above 85% are presented.

Converting signals between different electromagnetic modes is an asset for future information technologies. In general, slightly asymmetric optical nanoantennas enable the coupling between bright and dark modes sustained by an optical nanoantenna. However, the conversionefficiency might be very low. Here, we show that the additional incorporation of a quantum emitter allows to tremendously enhance this efficiency. The enhanced local density of states cycles the quantum emitter between its upper and lower level at an extremely hight rate; hence converting the energy very efficient. The process is robust with respect to possible experimental tolerances and adds a new ingredient to be exploited while studying and applying coupling phenomena in optical nanosystems.

We calculated the conversion-efficiency limit ηsc and the optimized subcell bandgap energies of 1 to 5 junction solar cells without and with intermediate reflectors under 1-sun AM1.5G and 1000-sun AM1.5D irradiations, particularly including the impact of internal radiative efficiency (ηint) below unity for realistic subcell materials on the basis of an extended detailed-balance theory. We found that the conversion-efficiency limit ηsc significantly drops when the geometric mean ηint* of all subcell ηint in the stack reduces from 1 to 0.1, and that ηsc degrades linearly to logηint* for ηint* below 0.1. For ηint*<0.1 differences in ηsc due to additional intermediate reflectors became very small if all subcells are optically thick for sun light. We obtained characteristic optimized bandgap energies, which reflect both ηint* decrease and AM1.5 spectral gaps. These results provide realistic efficiency targets and design principles.

Cyanobacteria provide an efficient system for producing H{sub 2} from water using solar energy. The energy conversionefficiency can be defined by the ratio of H{sub 2} produced to the light energy absorbed. An IR and opalescent plate method was used to measure the light energy absorbed. Since cyanobacteria absorb light in the visible range but not in the infrared range, the net amount of light energy absorbed by the cells can be estimated by measuring the IR and visible light intensities transmitted through the biochamber. A rectangular biochamber was used for measuring the conversionefficiency from light energy to H{sub 2} energy. A quantum meter and radiometer were used to measure the light intensity transmitted through the chamber. Anabaena variabilis was cultured in a BG11 medium with 3.6mM NaNO{sub 3} and the light intensity was 40-50{mu}mol/m{sup 2}/s in the growth phase and 120-140{mu}mol/m{sup 2}/s in the H{sub 2} production phase. The maximum H{sub 2} production was 50ml for 40h and cell density was 1.2g/l. The H{sub 2} production rate was 4.1ml H{sub 2}/g dry cell weight/h. Based on the light absorbed in the H{sub 2} production phase, the energy conversionefficiency from light to H{sub 2} was 1.5% on average and 3.9% at the maximum. Based on the light energy absorbed in the cell growth and H{sub 2} production phases, the energy conversionefficiency was 1.1% on average. (author)

Full Text Available Solar Cell Capacitance Simulator in 1 Dimension (SCAPS-1D is used to investigate the possibility of realizing ultrathin CdTe based solar cells with high and stable conversionefficiency. In the first step, we modified the conventional cell structure by substituting the CdS window layer with a CdS:O film having a wide band gap ranging from 2.42 to 3.17 eV. Thereafter, we simulated the quantum efficiency, as well as the parameters of J-V characteristics, and showed how the thickness of CdS:O layer influences output parameters of Glass/SnO2/ZTO/CdS:O/CdTe1-xSx/CdTe/Ni reference cell. High conversionefficiency of 17.30% has been found using CdTe1-xSx (x=0.12 and CdTe layers of thickness 15 nm and 4 μm, respectively. Secondly, we introduced a BSR layer between the absorber layer and back metal contact, which led to Glass/SnO2/ZTO/CdS:O/CdTe1-xSx/CdTe/BSR/Ni configuration. We found that a few nanometers (about 5 nm of CdTe1-xSx layer is sufficient to obtain high conversionefficiency. For BSR layer, different materials with large band gap, such as ZnTe, Cu2Te, and p+-CdTe, have been used in order to reduce minority carrier recombination at the back contact. When ZnTe is used, high conversionefficiency of 21.65% and better stability are obtained, compared to other BSR.

A process is known for separating the hydrocarbons contained in the outside air via chemical absorption filters and for converting the CO into harmless CO{sub 2} by means of a catalyst. However, it proves to be a disadvantage that the catalyst in the CO conversion is saturated by humidity and becomes ineffective. In order to overcome this disadvantage, it is proposed, according to the invention, that a chemical absorption filter layer to separate acid harmful gases and/or those containing hydrocarbons on the clean gas side is provided with a cassette-shaped, easily replaceable catalyst layer which can be placed on it, which consists of a drying layer, preferably silica gel, and a subsequent hopkalite layer, where the cassettes are inserted in reusable transport containers which must be closed airtight. The transport containers can consist of plastic envelopes, which are provided with a damp-proof means of closing. (orig.).

Improving plant energy conversionefficiency is crucial for increasing food and bioenergy crop production and yields. This study statistically quantifies the effects of climate/weather factors and management techniques on energy conversionefficiency from 140 published studies and provides a quantit...

This paper presents the optimum energy conversion conditions of stationary photovoltaic panels used for electrical power generation. The results are arrived at after performing calculations for 180 days in a given year at the latitude of St. John's, Newfoundland. The latitude of this city is close to other Canadian major population centers. Various angular orientations of sun's rays on the earth are considered. On a given day, the incident energy flux of sun is resolved into three components, and the conversionefficiency is based on the flux normal to the panels. The efficiency of conversion of the incident energy is measured with respect to a solar tracking process. The numbers of days in a given year are divided into two groups - one between the winter solstice and the spring equinox, and another between the spring equinox and the summer solstice. The results show the existence of two maxima, one for each of the two periods. By setting the panels at each of these maxima, very significant improvement in energy conversion can be achieved. (author)

Stereoscopic video is the new era in video viewing and has wide applications such as medicine, satellite imaging and 3D Television. Such stereo content can be generated directly using S3D cameras. However, this approach requires expensive setup and hence converting monoscopic content to S3D becomes a viable approach. This paper proposes a depth-based algorithm for monoscopic to stereoscopic video conversion by using the y axis co-ordinates of the bottom-most pixels of foreground objects. This code can be used for arbitrary videos without prior database training. It does not face the limitations of single monocular depth cues nor does it combine depth cues, thus consuming less processing time without affecting the efficiency of the 3D video output. The algorithm, though not comparable to real-time, is faster than the other available 2D to 3D video conversion techniques in the average ratio of 1:8 to 1:20, essentially qualifying as high-speed. It is an automatic conversion scheme, hence directly gives the 3D video output without human intervention and with the above mentioned features becomes an ideal choice for efficient monoscopic to stereoscopic video conversion. [Figure not available: see fulltext.

Conversion of biomass to fuels remains as one of the most promising approach to support our energy needs. It has been previously shown that the gasification of non-edible cellulosic biomass can be used to derive fuels like methanol and dimethyl ether (DME). However, the use of methanol and DME is limited due to the fact that they have low energy densities, poor lubricity and lower viscosity when compared to long-chain hydrocarbons. Increasing the blending percentage can also lead to undesired amounts of oxygenated molecules in the transportation fuel infrastructure, which restrict their applicability as jet or diesel fuels. Consequently, the petroleum-derived hydrocarbons remain as the main constituent of the middle-distillate based fuels. One way to increase the share of biofuels in middle-distillates is to use methanol/DME as building blocks for producing renewable, energy-dense hydrocarbons. One way to achieve this is by catalytically converting the DME and methanol to light olefins, followed by oligomerization to higher molecular weight premium alkanes, which can directly be used as kerosene/diesel fuels. Here, we report the catalytic dimerization of biomass-derived deoxygenated olefins into transportation fuel-range hydrocarbons under liquid-phase stirred-batch conditions. Specifically, the effect of operating conditions, such as reaction temperature, solvent-type, reaction duration and olefin-structure, on the conversion, selectivity and kinetics of dimerization of triptene (2,3,3-trimethyl-1-butene) were investigated. Triptene, as previously reported, is one of the major products of DME-homologation reaction over a BEA zeolite4. We show that triptene can be converted to high quality middle-distillates using a commercially available ion-exchange acid resin, Amberlyst-35 (dry) by the process of catalytic dimerization.

Full Text Available Stopping the plasma-enhanced chemical vapor deposition (PECVD once and maintaining the film in a vacuum for 30 s were performed. This was done several times during the formation of a film of i-layer microcrystalline silicon (μc-Si:H used in thin-film silicon tandem solar cells. This process aimed to reduce defect regions which occur due to collision with neighboring grains as the film becomes thicker. As a result, high crystallinity (Xc of μc-Si:H was obtained. Eventually, a solar cell using this process improved the conversionefficiency by 1.3% (0.14 points, compared with a normal-condition cell. In this paper, we propose an easy method to improve the conversionefficiency with PECVD.

We study the conversionefficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage. Heat leakage current from a hot electrode to a cold electrode is taken into account in the analysis of the harvester operation. Modeling of electrical output indicates that a maximum heat leakage current is not negligible because it is larger than that of the heat current harvested into electrical power. A reduction of heat leakage is required in this energy harvester in order to obtain efficient heat-to-electrical conversion. Multiple energy levels of a quantum dot can increase the output power of the harvester. Heavily doped colloidal semiconductor quantum dots are a possible candidate for a quantum-dot monolayer in the energy harvester to reduce heat leakage, scaling down device size, and increasing electrical output via multiple discrete energy levels.

Highlights: ► Femtomolar detection of PAHs such as perylene and benzopyrene was achieved. ► Photoexcited anthracene molecules transferred their energy to PAHs. ► Electronically excited PAHs were then excited to be ions. ► Two-photon ionization process was necessary to complete the ionization process. ► The number of defect sites could be reduced by the annealing procedure. - Abstract: Polycyclic aromatic hydrocarbons (PAHs), such as perylene and benzopyrene, doped at amounts on the order of femtomol (∼10{sup −15} mol) in anthracene crystals could be detected by laser desorption ionization mass spectrometry. Sensitivity was roughly 10{sup 3} times higher than that of LDI method in our experimental conditions. It was revealed from the excitation power dependence of the peak intensity of PAHs on the mass spectra that two-photon excitation in one UV pulse was necessary to complete the ionization process. It was also clarified that the number of defect sites that trap excitons generated in anthracene crystals could be reduced by the annealing procedure, by which an efficient energy transfer between anthracene and PAHs became possible.

We measure the conversionefficiency of 351 nm laser light to soft x-rays (0.1-5 keV) for Au, U and high Z mixtures 'cocktails' used for hohlraum wall materials in indirect drive ICF. We use spherical targets in a direct drive geometry, flattop laser pulses and laser smoothing with phase plates to achieve constant and uniform laser intensities of 10{sup 14} and 10{sup 15} W/cm{sup 2} over the target surface that are relevant for the future ignition experiments on NIF. The absolute time and spectrally-resolved radiation flux is measured with a multichannel soft x-ray power diagnostic. The conversionefficiency is then calculated by dividing the measured x-ray power by the incident laser power from which the measured laser backscattering losses is subtracted. After {approx}0.5 ns, the time resolved x-ray conversionefficiency reaches a slowly increasing plateau of 95% at 10{sup 14} W/cm{sup 2} laser intensity and of 80% at 10{sup 15} W/cm{sup 2}. The M-band flux (2-5 keV) is negligible at 10{sup 14} W/cm{sup 2} reaching {approx}1% of the total x-ray flux for all target materials. In contrast, the M-band flux is significant and depends on the target material at 10{sup 15} W/cm{sup 2} laser intensity, reaching values between 10% of the total flux for U and 27% for Au. Our LASNEX simulations show good agreement in conversionefficiency and radiated spectra with data when using XSN atomic physics model and a flux limiter of 0.15, but they underestimate the generated M-band flux.

A new approach of all optical wavelength converter based on four wave mixing (FWM) in a semiconductor optical amplifier (SOA) with the conjugate wave reflected by a fiber Bragg grating (FBG) and then amplified by the SOA is reported. By adjusting the pump power, the conversionefficiency could be improved 7～10dB with signal-to-background-noise-ratio (SBR) deteriorated 1～2dB, compared with traditional single pump four wave mixing.

Full Text Available Presents the results of studies of innovative materials in the field of renewable energy.The paper proposes a design and a formula for assessing energy efficiency of the heat pump air dryer, which uses zeotropic hydrocarbon mixtures of saturated hydrocarbons as a working agent and applies the principle of a counter-current heat exchanger with a variable temperature of both the working and the drying agents. Energy efficiency of the heat pump is achieved by means of obtaining a greater part of heat from renewable energy sources, in this case by cooling the air and condensing the water vapors in the heat pump. A conducted analysis identified correlations in establishing the marginal real coefficient of performance of the compression heat pump dryer running on zeotropic hydrocarbon mixtures and operating a cycle with variable temperatures of both the working and the drying agent in the evaporator and the condenser of the heat pump. According to the established correlations, the marginal real coefficient of performance of the compression heat pump dryers running on zeotropic hydrocarbon mixtures of 40 mol% of R600a and 60 mol% of R601 is 1.92 times higher than that of the same dryers running on only R600 (n-butane.

First we discuss some early work of Ulrike Feudel on structure formation in nonlinear reactions including ions and the efficiency of the conversion of chemical into electrical energy. Then we give some survey about isothermal energy conversion from chemical to higher forms of energy like mechanical, electrical and ecological energy. Isothermal means here that there are no temperature gradients within the model systems. We consider examples of energy conversion in several natural processes and in some devices like fuel cells. Further, as an example, we study analytically the dynamics and efficiency of a simple "active circuit" converting chemical into electrical energy and driving currents which is roughly modeling fuel cells. Finally we investigate an analogous ecological system of Lotka-Volterra type consisting of an "active species" consuming some passive "chemical food". We show analytically for both these models that the efficiency increases with the load, reaches values higher then 50 percent in a narrow regime of optimal load and goes beyond some maximal load abruptly to zero.

Solar Cell Capacitance Simulator in 1 Dimension (SCAPS-1D) is used to investigate the possibility of realizing ultrathin CdTe based solar cells with high and stable conversionefficiency. In the first step, we modified the conventional cell structure by substituting the CdS window layer with a CdS:O film having a wide band gap ranging from 2.42 to 3.17 eV. Thereafter, we simulated the quantum efficiency, as well as the parameters of J-V characteristics, and showed how the thickness of CdS:O l...

A two-year experiment was conducted in the field to measure the combined impact of tilling and N fertilization on various agronomic traits related to nitrogen (N) use efficiency and to grain yield in maize cultivated in the presence of a cover crop. Four years after conversion to no-till, a significant increase in N use efficiency N harvest index, N remobilization and N remobilization efficiency was observed both under no and high N fertilization conditions. Moreover, we observed that grain yield and grain N content were higher under no-till conditions only when N fertilizers were applied. Thus, agronomic practices based on continuous no-till appear to be a promising for increasing N use efficiency in maize. PMID:27711154

Growth rates of plant tissues depend on both the respiration rate and the efficiency with which carbon is incorporated into new structural biomass. Calorespirometric measurement of respiratory heat and CO2 rates, from which both efficiency and growth rate can be calculated, is a well established method for determining the effects of rapid temperature changes on the respiratory and growth properties of plant tissues. The effect of the alternative oxidase/cytochrome oxidase activity ratio on efficiency is calculated from first principles. Data on the temperature dependence of the substrate carbon conversionefficiency are tabulated. These data show that epsilon is maximum and approximately constant through the optimum growth temperature range and decreases rapidly as temperatures approach temperature limits to growth. The width of the maximum and the slopes of decreasing epsilon at high and low temperatures vary greatly with species, cultivars and accessions.

Efficient solar energy harvesting and photothermal conversion have essential importance for many practical applications. Here, we present a laser-induced cauliflower-shaped hierarchical surface nanostructure on a copper surface, which exhibits extremely high omnidirectional absorption efficiency over a broad electromagnetic spectral range from the UV to the near-infrared region. The measured average hemispherical absorptance is as high as 98% within the wavelength range of 200-800 nm, and the angle dependent specular reflectance stays below 0.1% within the 0-60° incident angle. Such a structured copper surface can exhibit an apparent heating up effect under the sunlight illumination. In the experiment of evaporating water, the structured surface yields an overall photothermal conversionefficiency over 60% under an illuminating solar power density of ~1 kW m-2. The presented technology provides a cost-effective, reliable, and simple way for realizing broadband omnidirectional light absorptive metal surfaces for efficient solar energy harvesting and utilization, which is highly demanded in various light harvesting, anti-reflection, and photothermal conversion applications. Since the structure is directly formed by femtosecond laser writing, it is quite suitable for mass production and can be easily extended to a large surface area.Efficient solar energy harvesting and photothermal conversion have essential importance for many practical applications. Here, we present a laser-induced cauliflower-shaped hierarchical surface nanostructure on a copper surface, which exhibits extremely high omnidirectional absorption efficiency over a broad electromagnetic spectral range from the UV to the near-infrared region. The measured average hemispherical absorptance is as high as 98% within the wavelength range of 200-800 nm, and the angle dependent specular reflectance stays below 0.1% within the 0-60° incident angle. Such a structured copper surface can exhibit an apparent

Botryococcus braunii, a green colonial microalga, is an unusually rich renewable source of hydrocarbons. In this study, wet microalgae harvest was thermally pretreated to enhance hydrocarbon recovery using a solvent extraction process. Samples containing a mixture of B. braunii and water were kept below 100 C for 10 min. The observed hydrocarbon recovery was 97.8% at 90 C. The extraction results suggest that the energy-intensive concentration and drying processes of the harvest could be eliminated. The proposed thermal pretreatment would revolutionize the conventional downstream processes. (author)

Electrokinetic power generation efficiency using a two-dimensional axisymmetrical model is numerically investigated. A finite-length nanoscale surface-charged cylindrical capillary with reservoirs connected at the capillary ends is considered as the physical domain. The Navier-Stokes, Laplace, Poisson, and Nernst-Planck equations are solved simultaneously to obtain the fluid flow, electrical potential, ion concentration and electrical current in the flow field. The energy conversionefficiency predicted using a one-dimensional model assuming an infinitely long channel, Boltzmann ion distribution and equal ionic electrical mobility is also carried out and compared with the two-dimensional result. The two-dimensional model results show that the electrostatic potential gradient resulting from the concentration changes at the capillary entrance and exit and fluid flow produce a conductive current that reduces the total current in the flow field. The conductive current due to the electrostatic potential gradient increases with the decrease in electrolyte bulk concentration and increase in surface charge density. This results in nonlinear variations in the electric current-voltage curve and maximum conversionefficiency as functions of the surface charge density and dimensionless Debye length when the electrolyte bulk concentration is low. Comparison of the maximum efficiencies predicted from one- and two-dimensional models indicates that the one-dimensional model is valid only when the dimensionless Debye length is large and the surface charge density is small because the electrostatic potential gradient is neglected. The two-dimensional model also predicts that optimum maximum energy conversionefficiency can be obtained when the dimensionless Debye length is equal to 2 and its magnitude increases with the increase in surface charge density. (author)

The main route to nitrogen dioxide (NOz) formation in combustion systems is through the oxidation of nitric oxide (NO). This process was originally invcstigafed in order to explain the high proportion of NOz found in NOx emissions from the exhaust of gas turbine engines [l]. Moreover, the understanding of the NO-NO2 conversion mechanism is relevant to a number of issues including NOz emission from unflued space heaters, development of NOx control technologies, behavior of NO/N02 in the atmosphere, formation and reduction chemistry of NOx, and the probe sampling techniques for NOx concentration measurements. Originally, the NO-NO2 conversion was thought to proceed through the rapid oxidation of NO by oxidative radicals without much attention to the effect of fuels on the conversion [2-41. Although, in later studies, it was revealed that the conversion was greatly promoted by small quantities of fuels such as hydrocarbons, Hz, CO, and methanol [S-9]. In our former experiment and model calculation of the NO-NO2 conversion in the mixing of hot combustion gas with cold air and nine different fuels [6], the results indicated that NO-NO2 conversion appeared only in the low temperature range, and showed a strong dependence on fuel type. Thus, the interaction between the NO-NO2 reactions and the oxidation reactions of the fuel in the low temperature range must be .understood in order to explain the effect of fuel type on the NO-NO2 conversion and consequently to predict the NO/NO2 emission levels from combustion systems.

The tandem concept involves stacking two or more cells with complementary absorption spectra in series or parallel connection, harvesting photons at the highest possible potential. It is strongly suggested that the roll-to-roll production of organic solar cells will employ the tandem concept...... to enhance the power conversionefficiency (PCE). However, due to the undeveloped deposition techniques, the challenges in ink formulation as well as the lack of commercially available high performance active materials, roll-to-roll fabrication of highly efficient organic tandem solar cells currently...... presents a major challenge. The reported high PCE values from lab-scale spin-coated devices are, of course, representative, but not helpful for commercialization. Here, organic tandem solar cells with exceptionally high fill factors and PCE values of 7.66% (on glass) and 5.56% (on flexible substrate...

This book describes synergetic innovation opportunities offered by combining the field of power conversion with the field of integrated circuit (IC) design. The authors demonstrate how integrating circuits enables increased operation frequency, which can be exploited in power converters to reduce drastically the size of the discrete passive components. The authors introduce multiple power converter circuits, which are very compact as result of their high level of integration. First, the limits of high-power-density low-voltage monolithic switched-capacitor DC-DC conversion are investigated to enable on-chip power granularization. AC-DC conversion from the mains to a low voltage DC is discussed, enabling an efficient and compact, lower-power auxiliary power supply to take over the power delivery during the standby mode of mains-connected appliances, allowing the main power converter of these devices to be shut down fully. Discusses high-power-density monolithic switched-capacitor DC-DC conversion in bulk CMOS,...

Full Text Available In this work, novel WO3-x/polyurethane (PU nanocomposites were prepared by ball milling followed by stirring using a planetary mixer/de-aerator. The effects of phase transformation (WO3 → WO2.8 → WO2.72 and different weight fractions of tungsten oxide on the optical performance, photothermal conversion, and thermal properties of the prepared nanocomposites were examined. It was found that the nanocomposites exhibited strong photoabsorption in the entire near-infrared (NIR region of 780–2500 nm and excellent photothermal conversion properties. This is because the particle size of WO3-x was greatly reduced by ball milling and they were well-dispersed in the polyurethane matrix. The higher concentration of oxygen vacancies in WO3-x contribute to the efficient absorption of NIR light and its conversion into thermal energy. In particular, WO2.72/PU nanocomposites showed strong NIR light absorption of ca. 92%, high photothermal conversion, and better thermal conductivity and absorptivity than other WO3/PU nanocomposites. Furthermore, when the nanocomposite with 7 wt % concentration of WO2.72 nanoparticles was irradiated with infrared light, the temperature of the nanocomposite increased rapidly and stabilized at 120 °C after 5 min. This temperature is 52 °C higher than that achieved by pure PU. These nanocomposites are suitable functional materials for solar collectors, smart coatings, and energy-saving applications.

Full Text Available In order to improve the electrical conversionefficiency of an electric tractor motor, a load torque based control strategy (LTCS is designed in this paper by using a particle swarm optimization algorithm (PSO. By mathematically modeling electric-mechanical performance and theoretical energy waste of the electric motor, as well as the transmission characteristics of the drivetrain, the objective function, control relationship, and analytical platform are established. Torque and rotation speed of the motor’s output shaft are defined as manipulated variables. LTCS searches the working points corresponding to the best energy conversionefficiency via PSO to control the running status of the electric motor and uses logic and fuzzy rules to fit the search initialization for load torque fluctuation. After using different plowing forces to imitate all the common tillage forces, the simulation of traction experiment is conducted, which proves that LTCS can make the tractor use electrical power efficiently and maintain agricultural applicability on farmland conditions. It provides a novel method of fabricating a more efficient electric motor used in the traction of an off-road vehicle.

We present a set of algorithms based on solo first principles calculations, to accurately calculate key properties of a DSC device including sunlight harvest, electron injection, electron-hole recombination, and open circuit voltages. Two series of D- π-A dyes are adopted as sample dyes. The short circuit current can be predicted by calculating the dyes' photo absorption, and the electron injection and recombination lifetime using real-time time-dependent density functional theory (TDDFT) simulations. Open circuit voltage can be reproduced by calculating energy difference between the quasi-Fermi level of electrons in the semiconductor and the electrolyte redox potential, considering the influence of electron recombination. Based on timescales obtained from real time TDDFT dynamics for excited states, the estimated power conversionefficiency of DSC fits nicely with the experiment, with deviation below 1-2%. Light harvesting efficiency, incident photon-to-electron conversionefficiency and the current-voltage characteristics can also be well reproduced. The predicted efficiency can serve as either an ideal limit for optimizing photovoltaic performance of a given dye, or a virtual device that closely mimicking the performance of a real device under different experimental settings.

In recent studies of inorganic materials for energy applications, surface modification processes have been shown to be among the most effective methods to enhance the performance of devices. Here, we demonstrate a facile nano-decoration method which is generally applicable to anatase TiO2 nanostructures, as well as a nano-decorated hierarchical TiO2 nanostructure which improves the energy conversionefficiency of a dye-sensitized solar cell (DSSC). Using a facile sol-gel method, 0-D, 1-D, and 2-D type anatase TiO2 nanostructures were decorated with 200 nm long anatase TiO2 nanorods to create various hierarchical nanostructures. A structural analysis reveals that the branched nanorod has a highly crystalline anatase phase with anisotropic growth in the [001] longitudinal direction. When one of the hierarchical structures, a chestnut bur-like nanostructure, was employed in a dye-sensitized solar cell as a scattering layer, offering increased dye-loading properties, preserving a sufficient level of light-scattering ability and preserving superior charge transport and recombination properties as well, the energy conversionefficiency of the cell improved by 19% (from 7.16% to 9.09%) compared to a cell with a 0-D TiO2 sphere as a scattering layer. This generally applicable anatase nanorod-decorating method offers potential applications in various energy-conversion applications, especially in DSSCs, quantum-dot solar cells, photoelectrochemical water-splitting devices, photocatalysis, and lithium ion batteries.

The results of study of methane conversion under non-oxidative conditions over molybdenum containing zeolite catalysts prepared by solid-phase synthesis using nanosized molybdenum powder are presented. The kinetic mechanisms of the process behavior under different conditions of methane dehydroaromatization are determined. It is shown that nonoxidative conversion of methane can occur both in the external diffusion and kinetic regions, depending on the methane flow rate. It is found out, that the optimum temperature of the methane conversion is 750 °C. It is shown that increased methane conversion is observed at the feed space velocity of methane decreasing from 1500 to 500 h-1.

The efficiency with which developing sunflower embryos convert substrates into seed storage reserves was determined by labeling embryos with [U-(14)C6]glucose or [U-(14)C5]glutamine and measuring their conversion to CO2, oil, protein and other biomass compounds. The average carbon conversionefficiency was 50%, which contrasts with a value of over 80% previously observed in Brassica napus embryos (Goffman et al., 2005), in which light and the RuBisCO bypass pathway allow more efficientconversion of hexose to oil. Labeling levels after incubating sunflower embryos with [U-(14)C4]malate indicated that some carbon from malate enters the plastidic compartment and contributes to oil synthesis. To test this and to map the underlying pattern of metabolic fluxes, separate experiments were carried out in which embryos were labeled to isotopic steady state using [1-(13)C1]glucose, [2-(13)C1]glucose, or [U-(13)C5]glutamine. The resultant labeling in sugars, starch, fatty acids and amino acids was analyzed by NMR and GC-MS. The fluxes through intermediary metabolism were then quantified by computer-aided modeling. The resulting flux map accounted well for the labeling data, was in good agreement with the observed carbon efficiency, and was further validated by testing for agreement with gas exchange measurements. The map shows that the influx of malate into oil is low and that flux through futile cycles (wasting ATP) is low, which contrasts with the high rates previously determined for growing root tips and heterotrophic cell cultures.

We bring out a non-trivial coupling of the intrinsic wettability, surface charge and electrokinetic energy conversion characteristics of nanofluidic devices. Our analyses demonstrate that nanofluidic energy conversionefficiencies may get amplified with increase in surface charge density, not perpetually, but only over a narrow regime of low surface charges, and may get significantly arrested to reach a plateau beyond a threshold surface charging condition, as attributed to a complex interplay between fluid structuration and ionic transport within a charged interfacial layer. We explain the corresponding findings from our molecular dynamics simulations with the aid of a simple modified continuum based theory. We attribute our findings to hitherto-unexplored four-way integration of surface charge, interfacial slip, ionic transport, and the water molecule structuration. The consequent complex non-linear nature of the energy transfer characteristics may bear far-ranging scientific and technological implications ...

Plasmonics can enhance solar energy conversion in semiconductors by light trapping, hot electron transfer, and plasmon-induced resonance energy transfer (PIRET). The multifaceted response of the plasmon and multiple interaction pathways with the semiconductor makes optimization challenging, hindering design of efficient plasmonic architectures. Therefore, in this paper we use a density matrix model to capture the interplay between scattering, hot electrons, and dipole-dipole coupling through the plasmon's dephasing, including both the coherent and incoherent dynamics necessary for interactions on the plasmon's timescale. The model is extended to Shockley-Queisser limit calculations for both photovoltaics and solar-to-chemical conversion, revealing the optimal application of each enhancement mechanism based on plasmon energy, semiconductor energy, and plasmon dephasing. The results guide application of plasmonic solar-energy harvesting, showing which enhancement mechanism is most appropriate for a given semiconductor's weakness, and what nanostructures can achieve the maximum enhancement.

The nonlinear optical process of spontaneous parametric down-conversion (SPDC) is widely studied for applications in quantum information science due to its ability to produce two photons that can be entangled in many degrees of freedom. For applications in quantum communication, two metrics of this process are particularly important: heralding efficiency and total joint rate. Here, we derive expressions for both quantities for a variety of different beam geometries and frequencies. We pay specific attention to the spectrum of both biphotons and individual photons. We reveal the underlying mechanisms responsible for the spectral shape and show they differ for different geometries and frequencies. We then use these spectra to calculate heralding efficiency and joint count rate and examine how each of these metrics changes with different geometries, frequencies, and spectral filtering and beam parameters. Interestingly, we find very high heralding efficiencies are achievable for collinear geometries, while nonco...

The electromagnetic spectrum and the photoelectric conversionefficiency of the silicon hexagonal nanoconical hole (SiHNH) arrays based solar cells is systematically analyzed according to Rigorous Coupled Wave Analysis (RCWA) and Modal Transmission Line (MTL) theory. An ultimate efficiency of the optimized SiHNH arrays based solar cell is up to 31.92% in consideration of the absorption spectrum, 4.52% higher than that of silicon hexagonal nanoconical frustum (SiHNF) arrays. The absorption enhancement of the SiHNH arrays is due to its lower reflectance and more supported guided-mode resonances, and the enhanced ultimate efficiency is insensitive to bottom diameter (D(bot)) of nanoconical hole and the incident angle. The result provides an additional guideline for the nanostructure surface texturing fabrication design for photovoltaic applications.

The objective of this study was to test that additive genetic (co)variation for survival, growth rate, feed conversionefficiency, and resistance to viral haemorrhagic septicaemia (VHS) exists within a farmed population of rainbow trout. Thirty sires and 30 dams were mated by a partly factorial...... the predicted breeding values for VHS resistance and the predicted breeding values for the body weights, body length, and feed conversionefficiencies. These results demonstrate that additive genetic (co)variation for growth rate, feed conversionefficiency, and VHS resistance does exist within the farmed...

Full Text Available Hetero-junction organic photovoltaic (OPV cells consisting of donor (D and acceptor (A layers have been regarded as next-generation PV cells, because of their fascinating advantages, such as lightweight, low fabrication cost, resource free, and flexibility, when compared to those of conventional PV cells based on silicon and semiconductor compounds. However, the power conversionefficiency (η of the OPV cells has been still around 8%, though more than 10% efficiency has been required for their practical use. To fully optimize these OPV cells, it is necessary that the low mobility of carriers/excitons in the OPV cells and the open circuit voltage (VOC, of which origin has not been understood well, should be improved. In this review, we address an improvement of the mobility of carriers/excitons by controlling the crystal structure of a donor layer and address how to increase the VOC for zinc octaethylporphyrin [Zn(OEP]/C60 hetero-junction OPV cells [ITO/Zn(OEP/C60/Al]. It was found that crystallization of Zn(OEP films increases the number of inter-molecular charge transfer (IMCT excitons and enlarges the mobility of carriers and IMCT excitons, thus significantly improving the external quantum efficiency (EQE under illumination of the photoabsorption band due to the IMCT excitons. Conversely, charge accumulation of photo-generated carriers in the vicinity of the donor/acceptor (D/A interface was found to play a key role in determining the VOC for the OPV cells.

Hetero-junction organic photovoltaic (OPV) cells consisting of donor (D) and acceptor (A) layers have been regarded as next-generation PV cells, because of their fascinating advantages, such as lightweight, low fabrication cost, resource free, and flexibility, when compared to those of conventional PV cells based on silicon and semiconductor compounds. However, the power conversionefficiency (η) of the OPV cells has been still around 8%, though more than 10% efficiency has been required for their practical use. To fully optimize these OPV cells, it is necessary that the low mobility of carriers/excitons in the OPV cells and the open circuit voltage (V OC), of which origin has not been understood well, should be improved. In this review, we address an improvement of the mobility of carriers/excitons by controlling the crystal structure of a donor layer and address how to increase the V OC for zinc octaethylporphyrin [Zn(OEP)]/C60 hetero-junction OPV cells [ITO/Zn(OEP)/C60/Al]. It was found that crystallization of Zn(OEP) films increases the number of inter-molecular charge transfer (IMCT) excitons and enlarges the mobility of carriers and IMCT excitons, thus significantly improving the external quantum efficiency (EQE) under illumination of the photoabsorption band due to the IMCT excitons. Conversely, charge accumulation of photo-generated carriers in the vicinity of the donor/acceptor (D/A) interface was found to play a key role in determining the V OC for the OPV cells.

A gyrator that is capable of current-to-voltage conversion can be realized with a magnetoelectric (ME) composite of ferromagnetic and ferroelectric phases placed in a coil. Here, we report the dependence of the power conversionefficiency (PE) on the relative thickness of the two ferroic phases in a gyrator of Terfenol-D and PZT. Both experimental and theoretical results on PE as a function of composite parameters, such as thickness ratio of the ferroic layers (n), magnetic field bias (HBias) and several gyrator parameters, such as the resistance load (RL), were discussed. By decreasing the thickness ratio of Terfenol-D to composite (n = 0.28) in coil-ME gyrators, a high power efficiency of 73.9% was found at a fundamental resonance frequency of 72.5 kHz under a HBias of 1000 Oe and RL = 2.6 kΩ in experiments. At the same time, the non-linear mechanical loss was reduced by decreasing the value of n which resulted in a flat response over a wide HBias range. This improved power efficiency promises ME gyrators for power transfer devices.

Maximum thermoelectric energy conversionefficiencies are calculated using the conventional "constant property" model and the recently proposed "cumulative/average property" model (Kim et al. in Proc Natl Acad Sci USA 112:8205, 2015) for 18 high-performance thermoelectric materials. We find that the constant property model generally predicts higher energy conversionefficiency for nearly all materials and temperature differences studied. Although significant deviations are observed in some cases, on average the constant property model predicts an efficiency that is a factor of 1.16 larger than that predicted by the average property model, with even lower deviations for temperature differences typical of energy harvesting applications. Based on our analysis, we conclude that the conventional dimensionless figure of merit ZT obtained from the constant property model, while not applicable for some materials with strongly temperature-dependent thermoelectric properties, remains a simple yet useful metric for initial evaluation and/or comparison of thermoelectric materials, provided the ZT at the average temperature of projected operation, not the peak ZT, is used.

Plasmonic nanostructures are of potential in acting as a type of optical agents for cancer photothermal therapy. To effectively function as photothermal therapy agents, plasmonic nanostructures are strongly desired to have good biocompatibility and high photothermal conversionefficiencies. In this study, poly(diallyldimethylammonium chloride)-coated porous Pt nanoparticles are synthesized for photothermal therapy. The Pt nanoparticles possess broadband near-infrared light absorption in the range from 650 to 1200 nm, therefore allowing for selecting different laser wavelengths for photothermal therapy. The as-prepared Pt nanoparticles exhibit remarkable photothermal conversionefficiencies under 809 and 980 nm laser irradiation. In vitro studies indicate that the Pt nanoparticles display good biocompatibility and high cellular uptake efficiencies through an endocytosis pathway. Photothermal heating using 808 nm laser irradiation (>7.0 W cm(-2) , 3 min) leads to notable cytotoxic effect, and more than 70% of cells are photothermally ablated after 3 min irradiation at 8.4 W cm(-2) . Furthermore, simultaneous application of photothermal therapy synergistically enhances the cytotoxicity of an anti-cancer drug doxorubicin. Therefore, the porous Pt nanoparticles have great potential as an attractive photothermal agent for cancer therapy.

Full Text Available In this article, 20 kW ocean thermal energy conversion with a vapor–vapor ejector is newly proposed. As a vapor–vapor ejector is installed in the system, the pressure difference between the turbine inlet and outlet increases. Therefore, the amount of the working fluid required for the total turbine work of 20 kW is less than when no vapor–vapor ejector is installed. Therefore, installing a vapor–vapor ejector in the system decreases the evaporation capacity and the pump work. The performance analysis considered the outlet pressure of the high-stage turbine, the mass flow ratio of the working fluid at the outlet of a separator just after the high-stage turbine, and the nozzle diameters of the vapor–vapor ejector. As the outlet pressure of high-stage turbine becomes lower, the turbine gross power of high-stage turbine and system efficiency increase although lower outlet pressure of high-stage turbine results in lower ejector performance. Similarly, in terms of mass flow ratio, the highest system efficiency was shown at mass flow ratio of 0.4 at the outlet of a separator just after the high-stage turbine. On the other hand, the performance of the ejector at mass flow ratio of 0.5 at the outlet of a separator was largest. When the nozzle diameters of the vapor–vapor ejector are properly designed, the vapor–vapor ejector shows the highest performance. After the optimization of the operation parameters, system efficiency of the proposed ocean thermal energy conversion power cycle was 2.47%, relatively 15% higher than that of the basic ocean thermal energy conversion power cycle (2.2%.

This Research Article describes a cooperative plasmonic effect on improving the performance of organic solar cells. When Au nanorods(NRs) are incorporated into the active layers, the designed project shows superior enhanced light absorption behavior comparing with control devices, which leads to the realization of organic solar cell with power conversionefficiency of 6.83%, accounting for 18.9% improvement. Further investigations unravel the influence of plasmonic nanostructures on light trapping, exciton generation, dissociation, and charge recombination and transport inside the thin films devices. Moreover, the introduction of high-conductivity Au NRs improves electrical conductivity of the whole device, which contributes to the enhanced fill factor.

This paper reports the theoretical and experimental work on converting focused Nd-glass laser radiation of LI-11 facility into kilovolt X-ray line emission in laser-heated NaF plasma.This conversionefficiency ε turns out to he in the range from 0.2% to 1% for the laser (λ=1.06μm) power density changing from 10×1013 to 3.5×1013 W/cm2 The relationship between ε and λ has also been discussed.Simultaneously,theoretical results are compared with the experimental.

The conversionefficiency of ultra short-pulse laser radiation to K-{alpha} x-rays has been measured for various chlorine-containing targets to be used as x-ray scattering probes of dense plasmas. The spectral and temporal properties of these sources will allow spectrally-resolved x-ray scattering probing with picosecond temporal resolution required for measuring the plasma conditions in inertial confinement fusion experiments. Simulations of x-ray scattering spectra from these plasmas show that fuel capsule density, capsule ablator density, and shock timing information may be inferred.

It was recognized that the introducing of a narrow metallic band states in the crystal structure of semiconductors make materials that they can be used as intermediate band materials for improving the power conversionefficiency of high band gap single junction solar cells. In these structures intermediate bands would serve as a "stepping stone" for photons with different energies to excite electrons from the valence to the conduction bands. Low-energy photons can be captured by this method that would pass through a conventional solar cell. An optimal IBSC (intermediate band solar cells) has a total band gap of about 1.95 eV and 3C-SiC has the closest band gap to this value (band gap of 2.2 eV). Excellent electronic properties of 3C-SiC such as high electron mobility and saturated electron drift velocity and its suitable band gap makes it an important alternative material for light harvesting technologies instead of conventional semiconductors like silicon. In this condition detailed balance analysis predicts a limiting efficiency of more than 55 % for an optimized, single junction intermediate band solar cell that it is higher than efficiency of an optimized two junction tandem solar cell. In this study we have analyzed Fe doped 3C-SiC by ab initio calculations for Fe concentration of 1.05, 1.85, 3.22, and 5.55 %. The results show conversionefficiency for designed solar cell change with altering in Fe contents. The maximum efficiency has been obtained for crystals with 3 % Fe3+ as dopant in 3C-SiC structure.

This project demonstrated microwave cracking of ethane with good product conversion and ethylene selectivity, with a short residence time ({approx}0.001 sec). The laboratory scale equipment was designed and built, along with concept designs for larger scale implementation. The system was operated below atmospheric pressures, in the range of 15-55 torr, with argon as a carrier gas. The measured products included hydrogen, methane, acetylene, and ethylene. The results followed similar trends to those predicted by the modeling software SPYRO{reg_sign}, with the exception that the microwave appeared to produce slightly lower amounts of ethylene and methane, although enhanced analytical analysis should reduce the difference. Continued testing will be required to verify these results and quantify the energy consumption of microwave vs. conventional. The microwave cracking process is an attractive option due to the possibility of selectively heating the reaction volume rather than the reactor walls, which may allow novel reactor designs that result in more efficient production of ethylene. Supplemental studies are needed to continue the laboratory testing and refine processing parameters.

The development status of a single-pulse distributed-energy-source electromagnetic railgun (ER) based on the design of Tower (1982) is reviewed. The five-stage ER is 3.65 m long, with energy inputs every 30 cm starting at the breech and a 12.7-mm-square bore cross section, and is powered by a 660-kJ 6-kV modular capacitor bank. Lexan cubes weighing 2.5 grams have been accelerated to velocities up to 8.5 km/sec at 500 kA and conversionefficiency up to 20 percent. Design goal for a 20-mm-sq-cross-section ER is acceleration of a 60-g projectile to 3-4 km/sec at 35-percent efficiency. Drawings, photographs, and graphs of performance are provided.

Nanogenerators capable of converting energy from mechanical sources to electricity with high effective efficiency using low-cost, nonsemiconducting, organic nanomaterials are attractive for many applications, including energy harvesters. In this work, near-field electrospinning is used to direct-write poly(vinylidene fluoride) (PVDF) nanofibers with in situ mechanical stretch and electrical poling characteristics to produce piezoelectric properties. Under mechanical stretching, nanogenerators have shown repeatable and consistent electrical outputs with energy conversionefficiency an order of magnitude higher than those made of PVDF thin films. The early onset of the nonlinear domain wall motions behavior has been identified as one mechanism responsible for the apparent high piezoelectricity in nanofibers, rendering them potentially advantageous for sensing and actuation applications.

Full Text Available Utilizing self-assembled nano-structured coatings on top of existing solar cells has thepotential to increase the total quantum efficiency of the cell using a simple and cheap process. In ourwork we have exploited the controlled absorption of nano-crystal with different band gaps to realizedown conversion artificial antennas that self-assembled on the device surface. The UV sun light isconverted to the visible light enhancing the solar cell performance in two complementary routes; a.protecting the solar cell and coatings from the UV illumination and therefore reducing the UVradiation damage. b. enhancing the total external quantum efficiency of the cell by one percent. Thisis achieved using a simple cheap process that can be adjusted to many different solar cells.

AlGaAs-GaAs heteroface p/sup +/-p-n solar cells have been fabricated directly on Si substrates using metalorganic chemical vapor deposition. GaAs on Si solar cell efficiency as high as exceeding 14.5% at AM1.5 was obtained by cleaning the substrate surface and repeating GaAs film growth interruption. This value is the highest ever reported for GaAs solar cells on Si substrates. Defects, which could not be observed in homoepitaxially grown GaAs film, were observed in the heteroepitaxial GaAs films through electron beam induced current image. Relatively low conversionefficiency of the GaAs cell on Si compared to the GaAs can be attributed to these defects.

Photoluminescence phenomena normally obey Stokes' law of luminescence according to which the emitted photon energy is typically lower than its excitation counterparts. Here we show that carbon nanotubes break this rule under one-photon excitation conditions. We found that the carbon nanotubes exhibit efficient near-infrared photoluminescence upon photoexcitation even at an energy lying >100–200 meV below that of the emission at room temperature. This apparently anomalous phenomenon is attributed to efficient one-phonon-assisted up-conversion processes resulting from unique excited-state dynamics emerging in an individual carbon nanotube with accidentally or intentionally embedded localized states. These findings may open new doors for energy harvesting, optoelectronics and deep-tissue photoluminescence imaging in the near-infrared optical range. PMID:26568250

In this work, natural dyes extracted from the same genus but different species flowers were used as sensitizer in Dye Sensitized Solar Cell (DSSC). To clearly show dye ingredients effect on electrical characteristics, the same genus flowers were selected. The dye ingredients were analyzed by Gas Chromatography Mass Spectrometer (GC-MS). The dyes were modified by a procedure that includes refluxing in acetone. All results indicate a relationship between gallic acid quantity in dyes and solar cell efficiency. To gain further insight, the solar cell parameters were obtained by using the single-diode and double-diode models and they were compared to each other. It was observed that the applied process causes a decrease in series resistance. How the modification process and gallic acid affect energy conversionefficiency were argued in detail in the frame of results that were obtained from solar cell models.

In recent studies of inorganic materials for energy applications, surface modification processes have been shown to be among the most effective methods to enhance the performance of devices. Here, we demonstrate a facile nano-decoration method which is generally applicable to anatase TiO2 nanostructures, as well as a nano-decorated hierarchical TiO2 nanostructure which improves the energy conversionefficiency of a dye-sensitized solar cell (DSSC). Using a facile sol-gel method, 0-D, 1-D, and 2-D type anatase TiO2 nanostructures were decorated with 200 nm long anatase TiO2 nanorods to create various hierarchical nanostructures. A structural analysis reveals that the branched nanorod has a highly crystalline anatase phase with anisotropic growth in the [001] longitudinal direction. When one of the hierarchical structures, a chestnut bur-like nanostructure, was employed in a dye-sensitized solar cell as a scattering layer, offering increased dye-loading properties, preserving a sufficient level of light-scattering ability and preserving superior charge transport and recombination properties as well, the energy conversionefficiency of the cell improved by 19% (from 7.16% to 9.09%) compared to a cell with a 0-D TiO2 sphere as a scattering layer. This generally applicable anatase nanorod-decorating method offers potential applications in various energy-conversion applications, especially in DSSCs, quantum-dot solar cells, photoelectrochemical water-splitting devices, photocatalysis, and lithium ion batteries.In recent studies of inorganic materials for energy applications, surface modification processes have been shown to be among the most effective methods to enhance the performance of devices. Here, we demonstrate a facile nano-decoration method which is generally applicable to anatase TiO2 nanostructures, as well as a nano-decorated hierarchical TiO2 nanostructure which improves the energy conversionefficiency of a dye-sensitized solar cell (DSSC). Using a facile

Despite their enhanced light trapping ability the performance of silicon nanowire array solar cells have, been stagnant with power conversionefficiencies barely breaking 10%. The problem is understood to be the consequence of a high photo-carrier recombination at the large surface area of the Si nanowire sidewalls. Here, by exploiting 1) electronic gating via an ionic liquid electrolyte to induce inversion in the n-type Si nanowires and 2) using a layer of single wall carbon nanotubes engineered to contact each nanowire tip and extract the minority carriers, we demonstrate silicon nanowire array solar cells with power conversionefficiencies of 15%. Our results allow for discrimination between the two principle means of avoiding front surface recombination: surface passivation and the use of local fields. A deleterious electrochemical reaction of the silicon due to the electrolyte gating is shown to be caused by oxygen/water entrained in the ionic liquid electrolyte. While encapsulation can avoid the issue a non-encapsulation based solution is also described. We gratefully acknowledge support from the National Science Foundation under ECCS-1232018.

The second law of thermodynamics imposes a strict limitation to the energy converted from direct solar radiation to useful work by a quantum device. This limitation requires that the amount of energy converted to useful work (energy in any form other than heat) can be no greater than the change in free energy of the radiation fields. Futhermore, in any real energy conversion device, not all of this available free energy in the radiation field can be converted to work because of basic limitations inherent in the device itself. A thermodynamic analysis of solar energy conversion by a completely general prototypical quantum device is presented. This device is completely described by two parameters, its operating temperature T sub R and the energy threshold of its absorption spectrum. An expression for the maximum thermodynamic efficiency of a quantum solar converter was derived in terms of these two parameters and the incident radiation spectrum. Efficiency curves for assumed solar spectral irradiance corresponding to air mass zero and air mass 1.5 are presented.

The industrialization chains and their products, which were formed from the process of the production of medicinal materials-prepared drug in pieces and deep processed product of Chinese material medica (CMM) resources, have generated large benefits of social and economic. However, The large of herb-medicine castoff of "non-medicinal parts" and "rejected materials" produced inevitably during the process of Chinese medicinal resources produce and process, and the residues, waste water and waste gas were produced during the manufactured and deep processed product of CMM. These lead to the waste of resources and environmental pollution. Our previous researches had proposed the "three utilization strategies" and "three types of resources models" of herb-medicine castoff according to the different physicochemical property of resources constitutes, resources potential and utility value of herb-medicine castoff. This article focus on the conversionefficiency of resources model and analysis the ways, technologies, practices, and application in herb-medicine cast off of the conversionefficiency of resources model based on the recycling economy theory of resources and thoughts of resources chemistry of CMM. These data may be promote and resolve the key problems limited the industrialization of Chinese material medica for long time and promote the realization of herb-medicine castoff resources utilization.

Organo-lead halide perovskites have attracted much attention for solar cell applications due to their unique optical and electrical properties. With either low-temperature solution processing or vacuum evaporation, the overall conversionefficiencies of perovskite solar cells with organic hole-transporting material were quickly improved to over 15% during the last 2 years. However, the organic hole-transporting materials used are normally quite expensive due to complicated synthetic procedure or high-purity requirement. Here, we demonstrate the application of an effective and cheap inorganic p-type hole-transporting material, copper thiocyanate, on lead halide perovskite-based devices. With low-temperature solution-process deposition method, a power conversionefficiency of 12.4% was achieved under full sun illumination. This work represents a well-defined cell configuration with optimized perovskite morphology by two times of lead iodide deposition, and opens the door for integration of a class of abundant and inexpensive material for photovoltaic application.

This work proposes the liquid hydrocarbon reductant (LHR) usage in the process of iron ore opening-up to a metallurgic range. Calcination process optimization of Lisakovsk gravity-magnetic concentrate (LGMC) was performed by the planning of experiments using Seidel – Gauss method. Iron content in the concentrate increases from 47,6 % to 54,17 % in optimal conditions.

Full Text Available This work proposes the liquid hydrocarbon reductant (LHR usage in the process of iron ore opening-up to a metallurgic range. Calcination process optimization of Lisakovsk gravity-magnetic concentrate (LGMC was performed by the planning of experiments using Seidel – Gauss method. Iron content in the concentrate increases from 47,6 % to 54,17 % in optimal conditions.

Full Text Available The paper considers modern approaches to usage of hydrocarbon-containing waste as energy resources and presents description of investigations, statistic materials, analysis results on formation of hydrocarbon-containing waste in the Republic of Belarus. Main problems pertaining to usage of waste as a fuel and technologies for their application have been given in the paper. The paper describes main results of the investigations and a method for efficient application of viscous hydrocarbon-containing waste as an energy-packed component and a binding material while producing a solid fuel. A technological scheme, a prototype industrial unit which are necessary to realize a method for obtaining multi-component solid fuel are represented in the paper. A paper also provides a model of technological process with efficient sequence of technological operations and parameters of optimum component composition. Main factors exerting significant structure-formation influence in creation of structural composition of multi-component solid fuel have been presented in the paper. The paper gives a graphical representation of the principle for selection of mixture particles of various coarseness to form a solid fuel while using a briquetting method and comprising viscous hydrocarbon-containing waste. A dependence of dimensionless concentration g of emissions into atmosphere during burning of two-component solid fuel has been described in the paper. The paper analyzes an influence of the developed methodology for emission calculation of multi-component solid fuels and reveals a possibility to optimize the component composition in accordance with ecological function and individual peculiar features of fuel-burning equipment. Special features concerning storage and transportation, advantages and disadvantages, comparative characteristics, practical applicability of the developed multi-component solid fuel have been considered and presented in the paper. The paper

This report was developed as part of the U.S. Department of Energy’s Bioenergy Technologies Office’s (BETO’s) efforts to enable the development of technologies for the production of infrastructure-compatible, cost-competitive liquid hydrocarbon fuels from lignocellulosic biomass feedstocks. The research funded by BETO is designed to advance the state of technology of biomass feedstock supply and logistics, conversion, and overall system sustainability. It is expected that these research improvements will be made within the 2022 timeframe. As part of their involvement in this research and development effort, the National Renewable Energy Laboratory and the Pacific Northwest National Laboratory investigate the economics of conversion pathways through the development of conceptual biorefinery process models and techno-economic analysis models. This report describes in detail one potential conversion process for the production of high-octane gasoline blendstock via indirect liquefaction of biomass. The processing steps of this pathway include the conversion of biomass to synthesis gas or syngas via indirect gasification, gas cleanup, catalytic conversion of syngas to methanol intermediate, methanol dehydration to dimethyl ether (DME), and catalytic conversion of DME to high-octane, gasoline-range hydrocarbon blendstock product. The conversion process configuration leverages technologies previously advanced by research funded by BETO and demonstrated in 2012 with the production of mixed alcohols from biomass. Biomass-derived syngas cleanup via reforming of tars and other hydrocarbons is one of the key technology advancements realized as part of this prior research and 2012 demonstrations. The process described in this report evaluates a new technology area for the downstream utilization of clean biomass-derived syngas for the production of high-octane hydrocarbon products through methanol and DME intermediates. In this process, methanol undergoes dehydration to

A fundamental study of both analog and digital pulse modulation methods is carried out. A novel class of multi-level pulse modulation methods - Phase Shifted Carrier Pulse Width Modulation (PSCPWM) - is introduced and show to have several advantageous features, primarily caused by the much improved synthesis of the modulating signal. Enhanced digital pulse modulation methods for digital Pulse Modulation Amplifier (PMA) systems are investigated, and a simple methodology for digital PWM modulator synthesis is devised. It is concluded, that the modulator performance is not a limitation in the system, regardless of the domain of modulator implementation. Power conversion in PMA systems is adressed from the perspective of both linearity and efficienty optimization. Based on detailed studies of the distortion mechanisms in the power conversion stage it is concluded, that this is the fundamental limitation on system performance due to several physical limitations. The analysis of general power stage efficiency concludes that dramatic improvements in energy efficiency are possible with PMA systems that are optimized for efficiency. A control system design methodology is devised as a platform for synthesis of robust control systems. Investigations of three fundamental control structures show that even simple control systems offer a remarkable value, although the considered topologies also have their limitations which is verified by practical evaluation in hardware. A novel control method is introduced - Multivariable Enhanced Cascade Control (MECC). MECC provides flexible control over all essential system parameters and is furthermore simple in realization. Practical evaluation of a MECC based PMA shows state-of-the-art performance. The application of non-linear control methods is investigated with the introduction of an enhanced non-linear control/modulator topology. Although the non-linear controller is theoretically interesting, the method proves to suffer from various

Photothermal excitation is a cantilever excitation method that enables stable and accurate operation for dynamic-mode AFM measurements. However, the low excitation efficiency of the method has often limited its application in practical studies. In this study, we propose a method for improving the photothermal excitation efficiency by coating cantilever backside surface near its fixed end with colloidal graphite as a photothermal conversion (PTC) layer. The excitation efficiency for a standard cantilever of PPP-NCHAuD with a spring constant of ≈40 N/m and a relatively stiff cantilever of AC55 with a spring constant of ≈140 N/m were improved by 6.1 times and 2.5 times, respectively, by coating with a PTC layer. We experimentally demonstrate high stability of the PTC layer in liquid by AFM imaging of a mica surface with atomic resolution in phosphate buffer saline solution for more than 2 h without any indication of possible contamination from the coating. The proposed method, using a PTC layer made of colloidal graphite, greatly enhances photothermal excitation efficiency even for a relatively stiff cantilever in liquid.

Full Text Available Photothermal excitation is a cantilever excitation method that enables stable and accurate operation for dynamic-mode AFM measurements. However, the low excitation efficiency of the method has often limited its application in practical studies. In this study, we propose a method for improving the photothermal excitation efficiency by coating cantilever backside surface near its fixed end with colloidal graphite as a photothermal conversion (PTC layer. The excitation efficiency for a standard cantilever of PPP-NCHAuD with a spring constant of ≈40 N/m and a relatively stiff cantilever of AC55 with a spring constant of ≈140 N/m were improved by 6.1 times and 2.5 times, respectively, by coating with a PTC layer. We experimentally demonstrate high stability of the PTC layer in liquid by AFM imaging of a mica surface with atomic resolution in phosphate buffer saline solution for more than 2 h without any indication of possible contamination from the coating. The proposed method, using a PTC layer made of colloidal graphite, greatly enhances photothermal excitation efficiency even for a relatively stiff cantilever in liquid.

The recent advances in perovskite solar cells (PSCs) created a tsunami effect in the photovoltaic community. PSCs are newfangled high-performance photovoltaic devices with low cost that are solution processable for large-scale energy production. The power conversionefficiency (PCE) of such devices experienced an unprecedented increase from 3.8 % to a certified value exceeding 20 %, demonstrating exceptional properties of perovskites as solar cell materials. A key advancement in perovskite solar cells, compared with dye-sensitized solar cells, occurred with the replacement of liquid electrolytes with solid-state hole-transporting materials (HTMs) such as 2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD), which contributed to enhanced PCE values and improved the cell stability. Following improvements in the perovskite crystallinity to produce a smooth, uniform morphology, the selective and efficient extraction of positive and negative charges in the device dictated the PCE of PSCs. In this Review, we focus mainly on the HTMs responsible for hole transport and extraction in PSCs, which is one of the essential components for efficient devices. Here, we describe the current state-of-the-art in molecular engineering of hole-transporting materials that are used in PSCs and highlight the requisites for market-viability of this technology. Finally, we include an outlook on molecular engineering of new functional HTMs for high efficiency PSCs.

Optical parametric oscillators (OPOs) utilizing quasi-phase matched materials offer an appealing alternative to direct laser sources. Quasi-phase matched materials provide a useful alternative to traditional birefringent nonlinear optical materials and through material engineering, higher nonlinear coefficients can now be accessed. Orientation patterned gallium arsenide (OPGaAs) is an ideal material because of its broad IR transmission and large nonlinear coefficient. In contrast to ferroelectric materials, such as lithium niobate, where the pattern is fabricated through electric poling, zincblende materials, like OPGaAs, are grown epitaxially with the designed pattern. Generating longwave output from a much shorter pump wavelength, however, is relatively inefficiency due to the large quantum defect when compared to similar devices operating in the 3 - 5 mum regime. One method to increase pump to idler conversionefficiency is to recycle the undesired and higher energy signal photons into additional idler photons via a second nonlinear stage. An external amplifier stage can be utilized, where the signal and idler from the OPO are sent to a second nonlinear crystal in which the idler is amplified at the expense of the signal. Alternatively, the second crystal can be placed within the original OPO cavity where the signal from the first-stage acts as the pump for the second crystal and the resonant intensity of the signal is higher. Pumping the second crystal within the OPO should lead to higher conversionefficiency into the longwave idler. The grating period needed for the second crystal to use the signal from the first crystal to produce additional idler has the fortuitous advantage that it will not phase match to the original pump wavelength, avoiding unwanted nonlinear interactions. Therefore, a simple linear cavity can be utilized where the pump from the first-stage will simply propagate through the second crystal without undesired results. Without this feature

The competence of two fungal isolates for degrading petroleum hydrocarbons was evaluated. The filamentous fungi were isolated from a crude oil-contaminated soil in northeastern Ecuador, and were 99 %-100 % similar in 18S rDNA sequence to the genus Geomyces. Their efficiencies of degradation were tested in vitro for 30 days, using medium and soil microcosm. Residual hydrocarbons were tracked by gas liquid chromatography with a flame ionization detector. The maximum removal percentages of total petroleum hydrocarbons were 77.3 % and 79.9 % for experiments in the medium and soil microcosm, respectively. The percent germination of cow pea (Vigna unguiculata) seeds was increased from 20 % to 100 % upon bioremediation. Isolates sporulated optimally on minimal salts agar medium at pH 5, 25°C temperature, 1 %-1.5 % substrate (crude oil) and 4-6 g L(-1) N-P-K. These findings suggest that these fungal isolates are potential degraders for bioremediation in crude oil-contaminated areas in Ecuador.

The lower conversionefficiency of nanocrystalline silicon (nc-Si:H) solar cells is a result of its lower photon absorption capability of nc-Si:H. To increase photon absorption of nc-Si:H, the Ag substrates were fabricated with optically functional patterns. Two types of patterns, with random and regular structures, were formed by direct imprint technology. Owing to these optically functional patterns, the scattering of reflected light at the surface of the patterned Ag was enhanced and the optical path became longer. Thus, a greater amount of photons was absorbed by the nc-Si:H layer. Compared to flat Ag (without a surface pattern), the light absorption value of the nc-Si:H layer with a random structure pattern was increased at wavelengths ranging from 600 to 1100 nm. In the case of the regular patterned Ag, the light absorption value of the nc-Si:H layer was higher than the flat Ag at 300 to 1100 nm. Subsequently, nc-Si:H solar cells constructed on the optically functional pattern exhibit a 15.7% higher J{sub sc} value and a 19.5% higher overall conversionefficiency, compared to an identical solar cell on flat Ag. - Highlights: • Optically functional patterns were fabricated by direct printing technique. • The light absorption of solar cells was increased by the patterned Ag substrate. • Current density of solar cells on patterned Ag increased by approximately 15.7%. • The efficiency of solar cells on patterned Ag increased by 19.5%.

In order to investigate the migration and accumulation efficiency of hydrocarbon natural gas in the Xujiaweizi fault depression, and to provide new evidence for the classification of its genesis, a source rock pyrolysis experiment in a closed system was designed and carried out. Based on this, kinetic models for describing gas generation from organic matter and carbon isotope fractionation during this process were established, calibrated and then extrapolated to geologic conditions by combining the thermal history data of the Xushen-1 Well. The results indicate that the coal measures in the Xujiaweizi fault depression are typical "high-efficiency gas sources", the natural gas generated from them has a high migration and accumulation efficiency, and consequently a large-scale natural gas accumulation occurred in the area. The highly/over matured coal measures in the Xujiaweizi fault depression generate coaliferons gas with a high δ13C1 value (＞ -20‰) at the late stage, making the carbon isotope composition of organic alkane gases abnormally heavy. In addition, the mixing and dissipation through the caprock of natural gas can result in the negative carbon isotope sequence (δ13C1 >δ13C2 >δ13C3 >δ13C4) of organic alkane gases, and the dissipation can also lead to the abnormally heavy carbon isotope composition of organic alkane gases. As for the discovery of inorganic nonhydrocarbon gas reservoirs, it can only serve as an accessorial evidence rather than a direct evidence that the hydrocarbon gas is inorganic. As a result, it needs stronger evidence to classify the hydrocarbon natural gas in the Xujiaweizi fault depression as inorganic gas.

This report was developed as part of the U.S. Department of Energy’s Bioenergy Technologies Office’s efforts to enable the development of technologies for the production of infrastructurecompatible, cost-competitive liquid hydrocarbon fuels from biomass. Specifically, this report details two conceptual designs based on projected product yields and quality improvements via catalyst development and process integration. It is expected that these research improvements will be made within the 2022 timeframe. The two conversion pathways detailed are (1) in situ and (2) ex situ upgrading of vapors produced from the fast pyrolysis of biomass. While the base case conceptual designs and underlying assumptions outline performance metrics for feasibility, it should be noted that these are only two of many other possibilities in this area of research. Other promising process design options emerging from the research will be considered for future techno-economic analysis.

Increasing crystallize size or aluminum content in MFI-type zeolites independently enhances the propagation of the aromatics-based methylation/dealkylation cycle relative to that of the olefins-based methylation/cracking cycle in methanol-to-hydrocarbons (MTH) conversion and consequentially results in higher ethene selectivity. Ethene selectivity increases monotonically with increasing aluminum content for HZSM-5 samples with nearly identical crystallite size consequent to an increase in the intracrystalline contact time analogous to our recent report detailing the effects of crystallite size (Khare et al., 2015) on MTH selectivity. The confected effects of crystallite size and site density on MTH selectivity can therefore, be correlated using a descriptor that represents the average number of acid sites that an olefin-precursor will interact with before elution.

Bio-oil from pyrolysis of mallee (Eucalyptus loxophleba ssp. gratiae) leaves differs from that obtained with wood by its content of cyclic ethers, terpenoids and N-containing organic compounds. Upgrading of the leaf bio-oil in methanol with a solid acid catalyst was investigated and it was found that the N-containing organics in the bio-oil lead to deactivation of the catalyst in the initial stage of exposure and have to be removed via employing high catalyst loading to allow the occurrence of other acid-catalysed reactions. Eucalyptol, the main cyclic ether in the bio-oil, could be converted into the aromatic hydrocarbon, p-cymene, through a series of intermediates including α-terpineol, terpinolene, and α-terpinene. Various steps such as ring-opening, dehydration, isomerisation, and aromatization were involved in the conversion of eucalyptol. The terpenoids in bio-oil could also be converted into aromatic hydrocarbons that can serve as starting materials for the synthesis of fine chemicals, via the similar processes.

Steel stirrers jacketed with polytetrafluoroethylene can be regarded as an ideal substrate for stirrer bar sorptive extraction. However, it is still a great challenge to immobilize graphene onto a polytetrafluoroethylene stirrer due to the high chemical resistance of the surface of a polytetrafluoroethylene stirrer. We describe here a method to modify the surface of polytetrafluoroethylene stirrers with graphene. In this work, graphene was used as the sorbent due to its excellent adsorption capability for aromatic compounds, such as polycyclic aromatic compounds. Graphene was successfully immobilized onto polytetrafluoroethylene-stirrer by a bio-inspired polydopamine functionalization method. The graphene-modified polytetrafluoroethylene-stirrer shows good stability and tolerance to stirring, ultrasonication, strong acidic and basic solutions, and to organic solvents. The multilayer coating was characterized by scanning electronic microscopy and Fourier transform infrared spectroscopy. After the optimization of some experimental conditions, the graphene-modified polytetrafluoroethylene stirrer was used for the stirrer bar sorptive extraction of polycyclic aromatic hydrocarbons, in which the binding between the polycyclic aromatic hydrocarbons and the graphene layer was mainly based on π-π stacking and hydrophobic interactions. The graphene-modified polytetrafluoroethylene-stirrer-based stirrer bar sorptive extraction and high-performance liquid chromatography method was developed for the determination of polycyclic aromatic hydrocarbons with great extraction efficiency, with enrichment factors from 18 to 62. The method has low limits of detection of 1-5 pg/mL, wide linear range (5-100 and 10-200 pg/mL), good linearity (R ≥ 0.9957) and good reproducibility (RSD ≤ 6.45%). The proposed method has been applied to determine polycyclic aromatic hydrocarbons in real dust samples. Good recoveries were obtained, ranging from 88.53 to 109.43%.

Full Text Available The paper contains a comparative efficiency analysis pertaining to application of existing technological methods for suppression of nitric oxide formation in heating boilers of heat generators. A special attention has been given to investigation of NOx emission reduction while burning hydrocarbon fuel with the help of oxygen-enriched air. The calculations have demonstrated that while enriching oxidizer with the help of oxygen up to 50 % (by volume it is possible to reduce volume of NOx formation (while burning fuel unit by 21 %.

The efficacy of plants as means of decontaminating hydrocarbon-polluted soil has been studied. Ditch reed (Phragmites australis) and alfalfa (Medicago sativa) markedly intensified processes of pollutant destruction, the effect being particularly pronounced in the case of polycyclic aromatic hydrocarbons (PAHs). Comparative analysis of microflora in soils (including those devoid of plants and rhizosphere) demonstrated that, in addition to preventing the pollutant-induced decrease in the amount of heterotrophic microorganisms, the plants stimulated their development, significantly increasing the population of destructors. Effects of plants on major physiological groups of soil microorganisms under conditions of pollution were ambiguous. The rhizosphere consortium of alfalfa was less susceptible to effects of pollutants than that of reed.

Recent understanding that specific algae have high hydrocarbon production potential has attracted considerable attention. Botryococcus braunii is a microalga with an extracellular hydrocarbon matrix, which makes it an appropriate green energy source. This study focuses on extracting oil from the microalgae matrix rather than the cells, eliminating the need for an excessive electric field to create electro-permeabilization. In such a way, technical limitations due to high extraction energy and cost can be overcome. Here, nanosecond pulsed electric fields (nsPEF) with 80 ns duration and 20-65 kV/cm electric fields were applied. To understand the extraction mechanism, the structure of the algae was accurately studied under fluorescence microscope; extraction was quantified using image analysis; quality of extraction was examined by thin-layer chromatography (TLC); and the cell/matrix separation was observed real-time under a microscope during nsPEF application. Furthermore, optimization was carried out by screening values of electric fields, pulse repetition frequencies, and energy spent. The results offer a novel method applicable for fast and continues hydrocarbon extraction process at low energy cost.

Neural differentiation of human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) can produce a valuable and robust source of human neural cell subtypes, holding great promise for the study of neurogenesis and development, and for treating neurological diseases. However, current hESCs and hiPSCs neural differentiation protocols require either animal factors or embryoid body formation, which decreases efficiency and yield, and strongly limits medical applications. Here we develop a simple, animal-free protocol for neural conversion of both hESCs and hiPSCs in adherent culture conditions. A simple medium formula including insulin induces the direct conversion of >98% of hESCs and hiPSCs into expandable, transplantable, and functional neural progenitors with neural rosette characteristics. Further differentiation of neural progenitors into dopaminergic and spinal motoneurons as well as astrocytes and oligodendrocytes indicates that these neural progenitors retain responsiveness to instructive cues revealing the robust applicability of the protocol in the treatment of different neurodegenerative diseases. The fact that this protocol includes animal-free medium and human extracellular matrix components avoiding embryoid bodies makes this protocol suitable for the use in clinic. Stem Cells Translational Medicine 2017;6:1217-1226.

Full Text Available Characterizations of biomass and coal were undertaken in order to compare their properties and determine the combustion characteristics of both feedstocks. The study was also intended to establish whether the biomass (corn stover used for this study is a suitable feedstock for blending with coal for the purpose of cogasification based on composition and properties. Proximate and ultimate analyses as well as energy value of both samples including their blends were undertaken and results showed that corn stover is a biomass material well suited for blending with coal for the purpose of cogasification, given its high volatile matter content which was measured and found to be 75.3% and its low ash content of 3.3% including its moderate calorific value of 16.1%. The results of the compositional analyses of both pure and blended samples of corn stover and coal were used to conduct computer simulation of the cogasification processes in order to establish the best blend that would result in optimum cogasification efficiency under standard gasifier operating conditions. The final result of the cogasification simulation process indicated that 90% corn stover/10% coal resulted in a maximum efficiency of about 58% because conversion was efficiently achieved at a temperature that is intermediate to that of coal and corn stover independently.

Full Text Available Biomass gasification is the thermochemical conversion of biomass materials into a producer gas, which is a mixture of carbon monoxide, carbon dioxide, methane, hydrogen, nitrogen and water vapour. The 180Nm3/h System Johansson Biomass Gasifier (SJBG at Eskom research and Innovation Centre is used for research and development initiatives, and also for demonstration purposes. The aim of this research was to investigate the efficiency of the gasifier and. This is done through an analysis of the gas profiles at the gasifier using a custom-built gas and temperature measurement system. Non-Dispersive Infrared gas detection technique is applied to monitor the volume and quality of producer gas. Palladium/Nickel gas sensing is applied to monitor the hydrogen content in the gas stream. Temperature in the gasifier is monitored through the use of type K thermocouples. The gas and temperature sensors are connected to the data logger interfaced to a computer. The heating value of the producer gas was determined from the percentage composition of the combustible gases. Evaluation of the efficiency of this gasifier was done before the installation of a 300Nm3/h at a rural village. The gasifier achieved an efficiency of 75% with an average gas heating value of 6MJ/Nm3.

The unique optical properties of nanometallic structures can be exploited to confine light at subwavelength scales. This excellent light trapping is critical to improve light absorption efficiency in nanoscale photovoltaic devices. Here, we apply a multiscale quantum mechanics/electromagnetics (QM/EM) method to model the current-voltage characteristics and optical properties of plasmonic nanowire-based solar cells. The QM/EM method features a combination of first-principles quantum mechanical treatment of the photoactive component and classical description of electromagnetic environment. The coupled optical-electrical QM/EM simulations demonstrate a dramatic enhancement for power conversionefficiency of nanowire solar cells due to the surface plasmon effect of nanometallic structures. The improvement is attributed to the enhanced scattering of light into the photoactive layer. We further investigate the optimal configuration of the nanostructured solar cell. Our QM/EM simulation result demonstrates that a further increase of internal quantum efficiency can be achieved by scattering light into the n-doped region of the device.

Full Text Available Dye-Sensitized Solar Cells (DSSCs, based on TiO2 and assembled using a dye from Beta vulgaris extract (BVE with Tetraethylorthosilicate (TEOS, are reported. The dye BVE/TEOS increased its UV resistance, rendering an increase in the cell lifetime; the performance of these solar cells was compared to those prepared with BVE without TEOS. The efficiency η for the solar energy conversion was, for BVE and BVE/TEOS, of 0.89% ± 0.006% and 0.68% ± 0.006% with a current density Jsc of 2.71 ± 0.003 mA/cm2 and 2.08 ± 0.003 mA/cm2, respectively, using in both cases an irradiation of 100 mW/cm2 at 25 °C. The efficiency of the BVE solar cell dropped from 0.9 ± 0.006 to 0.85 ± 0.006 after 72 h of operation, whereas for the BVE/TEOS, the efficiency remained practically constant in the same period of time.

In the application of solar energy, hydrogen is likely to be used as an energy carrier and a storage medium. Production of molecular hydrogen and oxygen from water requires energy input, which may come from solar energy in various ways. This thesis begins with a literature survey of the different conversion processes and the efficiencies, which is an introduction to a series of enclosed papers. These papers are: (1) Trapping of Minority Charge Carriers at Irradiated Semiconductor/Electrolyte Heterojunctions, (2) Model Calculations on Flat-Plate Solar Heat Collector With Integrated Solar Cells, and (3) Efficiencies and Physical Principles of Photolysis of Water By Microalgae. In the papers, The qualitative features of the ``illumination-current``-characteristic curve are deduced. The hypothesis is that trapping originates in some specific cases because of confinement, which leads to charge injections into energy states above that corresponding to the band edge. The quantitative features of certain hybrid photovoltaic/thermal configuration are deduced. An analysis of the theoretical and realizable efficiencies of the photolysis of water by micro algae is given. 151 refs., 18 figs., 1 table

initial weight) was recorded in 5 ppt salinity. Moulting frequency and intermoult period did not vary with variation in salinity. However, gross growth efficiency (K1=76.1%) and net growth efficiency (K2=82.5%) values were high and food conversion ratio...

Cladding-pumped Raman fiber lasers and amplifiers provide high-efficiencyconversionefficiency at high brightness enhancement. Differential loss is applied to both single-pass configurations appropriate for pulsed amplification and laser oscillator configurations applied to high average power cw source generation.

Inulooligosaccharides (IOS) represent an important class of oligosaccharides at industrial scale. An efficientconversion of inulin to IOS through endoinulinase from Aspergillus niger is presented. A 1482 bp codon optimized gene fragment encoding endoinulinase from A. niger DSM 2466 was cloned into pPIC9K vector and was transformed into Pichia pastoris KM71. Maximum activity of the recombinant endoinulinase, 858 U/mL, was obtained at 120 h of the high cell density fermentation process. The optimal conditions for inulin hydrolysis using the recombinant endoinulinase were investigated. IOS were harvested with a high concentration of 365.1 g/L and high yield up to 91.3%. IOS with different degrees of polymerization (DP, mainly DP 3-6) were distributed in the final reaction products.

Zero waste is a philosophy and a design principle of dealing with our waste stream for the 21st century. After reviewing the available information, the goal of zero waste from landfill is considered to be unachievable by using known and proven methods and approaches. The comparison of various technologies shows that the conversionefficiencies depend upon the type of system chosen for processing residual waste, and the best overall diversion rate of waste management system that can be achieved is about 71%. The maximum achievable overall diversion rate can be increased to approximate 92% if current environmental regulations to permit the routine use of the bottom ash or char for advanced thermal technologies.

With regard to accelerated introduction of high efficient energy conversion technology to developing countries, the paper investigates the countries' thoughts of the introduction of the technology and the status of the introduction bases. The countries for survey are the Philippines, Indonesia, Malaysia and Thailand. The Philippine government expects to develop cogeneration as well as large power sources and to widen effective use of natural energy. In Indonesia, they largely expect effective use of biomass energy using Stirling engines by international cooperation and the promoted local electrification using standalone distributed fuel cells. In Malaysia, they have great expectations of the introduction of air conditioning facilities using Stirling engines and the use of standalone distributed fuel cells for promotion of local electrification. Thailand hopes for the use of Stirling engines to air conditioning systems, and the development of solar Stirling generators with solar energy as a heat source and electric vehicles.

Defect control in Cu(In,Ga)Se2 (CIGS) materials, no matter what the defect type or density, is a significant issue, correlating directly to PV performance. These defects act as recombination centers and can be briefly categorized into interface recombination and Shockley-Read-Hall (SRH) recombination, both of which can lead to reduced PV performance. Here, we introduce an electrochemical passivation treatment for CIGS films that can lower the oxygen concentration at the CIGS surface as observed by X-ray photoelectron spectrometer analysis. Temperature-dependent J-V characteristics of CIGS solar cells reveal that interface recombination is suppressed and an improved rollover condition can be achieved following our electrochemical treatment. As a result, the surface defects are passivated, and the power conversionefficiency performance of the solar cell devices can be enhanced from 4.73 to 7.75%.

A means of assessing the relative impact of different renewable energy technologies on global warming has been developed. All power plants emit thermal energy to the atmosphere. Fossil fuel power plants also emit CO{sub 2} which accumulates in the atmosphere and provides an indirect increase in global warming via the greenhouse effect. A fossil fuel power plant may operate for some time before the global warming due to its CO{sub 2} emission exceeds the warming due to its direct heat emission. When a renewable energy power plant is deployed instead of a fossil fuel power plant there may be a significant time delay before the direct global warming effect is less than the combined direct and indirect global warming effect from an equivalent output coal fired plant - the ''business as usual'' case. Simple expressions are derived to calculate global temperature change as a function of ground reflectance and conversionefficiency for various types of fossil fuelled and renewable energy power plants. These expressions are used to assess the global warming mitigation potential of some proposed Australian renewable energy projects. The application of the expressions is extended to evaluate the deployment in Australia of current and new geo-engineering and carbon sequestration solutions to mitigate global warming. Principal findings are that warming mitigation depends strongly on the solar to electric conversionefficiency of renewable technologies, geo-engineering projects may offer more economic mitigation than renewable energy projects and the mitigation potential of reforestation projects depends strongly on the location of the projects. (author)

As a result of uncertain resource availability and growing populations, city managers are implementing conservation plans that aim to provide services for people while reducing household resource use. For example, in the US, municipalities are incentivizing homeowners to replace their water-intensive turfgrass lawns with water-efficient landscapes consisting of interspersed drought-tolerant shrubs and trees with rock or mulch groundcover (e.g. xeriscapes, rain gardens, water-wise landscapes). While these strategies are likely to reduce water demand, the consequences for other ecosystem services are unclear. Previous studies in controlled, experimental landscapes have shown that conversion from turfgrass to shrubs may lead to high rates of nutrient leaching from soils. However, little is known about the long-term biogeochemical consequences of this increasingly common land cover change across diverse homeowner management practices. We explored the fate of soil nitrogen (N) across a chronosequence of land cover change from turfgrass to water-efficient landscapes in privately owned yards in metropolitan Phoenix, Arizona, in the arid US Southwest. Soil nitrate ({{{{NO}}}3}--N) pools were four times larger in water-efficient landscapes (25 ± 4 kg {{{{NO}}}3}--N/ha 0-45 cm depth) compared to turfgrass lawns (6 ± 7 kg {{{{NO}}}3}--N/ha). Soil {{{{NO}}}3}--N also varied significantly with time since landscape conversion; the largest pools occurred at 9-13 years after turfgrass removal and declined to levels comparable to turfgrass thereafter. Variation in soil {{{{NO}}}3}--N with landscape age was strongly influenced by management practices related to soil water availability, including shrub cover, sub-surface plastic sheeting, and irrigation frequency. Our findings show that transitioning from turfgrass to water-efficient residential landscaping can lead to an accumulation of {{{{NO}}}3}--N that may be lost from the plant rooting zone over time following irrigation or

The goal of this research is to develop catalysts that directly convert methane and light hydrocarbons to intermediates that later can be converted to either liquid fuels or value-added chemicals, as economics dictate. During this reporting period, we synthesized several phthalocyanine catalysts supported on magnesia (MgO) in Task 3. In Task 4 we have tested these catalysts for oxidation of methane and did a number of blank experiments to determine the cause of the low methanol yield we have observed. Magnesia supported catalysts were prepared by first synthesizing the various metal tetrasulfophthalocyanines (TSPCs), converting them to the acid form, and then supporting these complexes on a basic support (MgO) by a neutralization reaction. The metals used were Ru, Pd, Cu, Fe, Co, Mn, and Mo. CoTSPC was also synthesized in zeolite Y using our standard template techniques described in Quarterly Report No. 1. These complexes were examined for catalytic activity in the oxidation of methane. The PdTSPC/MgO had greater activity, and oxidized some of the methane (selectivity of 2.8% from the methane oxidized at 375{degrees}C) to ethane. This is a much lower temperature for this reaction than previously reported in the literature. We also examined the reactivity of various components of the system in the oxidation of the product methanol. The reactor showed some activity for the oxidation of methanol to carbon dioxide. When zeolite or magnesia were added, this activity increased. The magnesia oxidized most of the methanol to carbon dioxide, while the zeolite reduced some of the methanol to hydrocarbons. With oxygen in the feed gas stream (i.e., the conditions of our methane oxidation), a very large fraction of the methanol was oxidized to carbon dioxide when passed over magnesia. From this, we can conclude that any methanol formed in the oxidation of methane would probably be destroyed very quickly on the catalyst bed.

Full Text Available The catalytic conversion of crude palm oil over HZSM-5 and HY zeolites modified with NiW as catalysts in the hydrocracking process was investigated. These zeolites supported by NiW catalysts were prepared employing the impregnation technique. NiW was added to the zeolites in order to induce bi-functional properties (both acid and metal sites in the catalysts. Subsequently, the catalysts were characterized by X-ray diffraction spectrometry (XRD, scanning electron microscope (SEM, transmission electron microscope (TEM, ammonia temperature programmed desorption (NH3-TPD andnitrogen adsorption-desorption isotherms analysis. The catalytic activity of prepared catalysts was evaluated through the conversion of crude palm oil to biofuels. These results indicate that the incorporation of NiW over HZSM-5 and HY zeolites improves the conversionefficiency and enhances the yield of biofuel (gasoline, kerosene, and diesel, possibly due to NiW promote of hydrogenation and dehydrogenation reaction.

In this project, we have developed the use of thin-film magnetic materials to improve in energy efficiency of digital computing applications by enabling integrated dc-dc power conversion and management with on-chip power inductors. Integrated voltage regulators also enables fine-grained power management, by providing dynamic scaling of the supply voltage in concert with the clock frequency of synchronous logic to throttle power consumption at periods of low computational demand. The voltage converter generates lower output voltages during periods of low computational performance requirements and higher output voltages during periods of high computational performance requirements. Implementation of integrated power conversion requires high-capacity energy storage devices, which are generally not available in traditional semiconductor processes. We achieve this with integration of thin-film magnetic materials into a conventional complementary metal-oxide-semiconductor (CMOS) process for high-quality on-chip power inductors. This project includes a body of work conducted to develop integrated switch-mode voltage regulators with thin-film magnetic power inductors. Soft-magnetic materials and inductor topologies are selected and optimized, with intent to maximize efficiency and current density of the integrated regulators. A custom integrated circuit (IC) is designed and fabricated in 45-nm CMOS silicon-on-insulator (SOI) to provide the control system and power-train necessary to drive the power inductors, in addition to providing a digital load for the converter. A silicon interposer is designed and fabricated in collaboration with IBM Research to integrate custom power inductors by chip stacking with the 45-nm CMOS integrated circuit, enabling power conversion with current density greater than 10A/mm2. The concepts and designs developed from this work enable significant improvements in performance-per-watt of future microprocessors in servers, desktops, and mobile

Sugarcane bagasse was torrefied to improve its quality in terms of properties prior to gasification. Torrefaction was undertaken at 300 °C in an inert atmosphere of N₂ at 10 °C·min(-1) heating rate. A residence time of 5 min allowed for rapid reaction of the material during torrefaction. Torrefied and untorrefied bagasse were characterized to compare their suitability as feedstocks for gasification. The results showed that torrefied bagasse had lower O-C and H-C atomic ratios of about 0.5 and 0.84 as compared to that of untorrefied bagasse with 0.82 and 1.55, respectively. A calorific value of about 20.29 MJ·kg(-1) was also measured for torrefied bagasse, which is around 13% higher than that for untorrefied bagasse with a value of ca. 17.9 MJ·kg(-1). This confirms the former as a much more suitable feedstock for gasification than the latter since efficiency of gasification is a function of feedstock calorific value. SEM results also revealed a fibrous structure and pith in the micrographs of both torrefied and untorrefied bagasse, indicating the carbonaceous nature of both materials, with torrefied bagasse exhibiting a more permeable structure with larger surface area, which are among the features that favour gasification. The gasification process of torrefied bagasse relied on computer simulation to establish the impact of torrefaction on gasification efficiency. Optimum efficiency was achieved with torrefied bagasse because of its slightly modified properties. Conversionefficiency of the gasification process of torrefied bagasse increased from 50% to approximately 60% after computer simulation, whereas that of untorrefied bagasse remained constant at 50%, even as the gasification time increased.

Efficient lead (Pb)-free inverted planar formamidinium tin triiodide (FASnI3) perovskite solar cells (PVSCs) are demonstrated. Our FASnI3 PVSCs achieved average power conversionefficiencies (PCEs) of 5.41% +/- 0.46% and a maximum PCE of 6.22% under forward voltage scan. The PVSCs exhibit small photocurrent-voltage hysteresis and high reproducibility. The champion cell showed a steady-state efficiency of almost equal to 6.00% for over 100 s.

As a new transduction technology, dielectric elastomer generators (DEGs) are capable of converting mechanical energy from diverse sources into electrical energy. However, their energy harvesting performance is strongly affected by the material viscoelasticity. Based on the finite-deformation viscoelasticity theory and the nonlinear coupled field theory for dielectric elastomers, this work presents a theoretical framework to model the performance of DEGs. Motivated by the recent experiments of DEGs with a triangular harvesting scheme, we propose a method to optimize the harvesting cycle, which could significantly improve the conversionefficiency of viscoelastic DEGs. From our simulation results, choosing a higher voltage power source appears to be an effective way to improve the performance of DEGs. In addition, optimizing the period of the discharging process of DEG can markedly increase its efficiency. Also, we have uncovered that the triangular harvesting scheme for DEGs, which is expected to harvest energy close to the maximum achievable energy, could be actually realized by choosing dielectric elastomers with a higher fraction of time-independent polymer networks. The theoretical framework and simulation results presented in this work are expected to benefit the optimal design of DEGs for different applications.

In order to meet the world's growing energy demand and reduce the impact of greenhouse gas emissions resulting from fossil fuel combustion, renewable plant-based feedstocks for biofuel production must be considered. The first-generation biofuels, derived from starches of edible feedstocks, such as corn, create competition between food and fuel resources, both for the crop itself and the land on which it is grown. As such, biofuel synthesized from non-edible plant biomass (lignocellulose) generated on marginal agricultural land will help to alleviate this competition. Eucalypts, the broadly defined taxa encompassing over 900 species of Eucalyptus, Corymbia, and Angophora are the most widely planted hardwood tree in the world, harvested mainly for timber, pulp and paper, and biomaterial products. More recently, due to their exceptional growth rate and amenability to grow under a wide range of environmental conditions, eucalypts are a leading option for the development of a sustainable lignocellulosic biofuels. However, efficientconversion of woody biomass into fermentable monomeric sugars is largely dependent on pretreatment of the cell wall, whose formation and complexity lend itself toward natural recalcitrance against its efficient deconstruction. A greater understanding of this complexity within the context of various pretreatments will allow the design of new and effective deconstruction processes for bioenergy production. In this review, we present the various pretreatment options for eucalypts, including research into understanding structure and formation of the eucalypt cell wall.

The electrokinetic energy conversion (EKEC) of hydraulic work directly into electrical energy has been investigated in charged polymeric membranes with different pore charge densities and characteristic diameters of the nanoporous network. The membranes were synthesized from blends of nitrocellulose and sulfonated polystyrene (SPS) and were comprehensively characterized with respect to structure, composition, and transport properties. It is shown that the SPS can be used as a sacrificial pore generation medium to tune the pore size and membrane porosity, which in turn highly affects the transport properties of the membranes. Furthermore, it is shown that very high EKEC efficiencies (>35%) are encountered in a rather narrow window of the properties of the nanoporous membrane network, that is, with pore diameters of ca. 10 nm and pore charge densities of 4.6 × 10(2) to 1.5 × 10(3) mol SO3(-) m(-3) for dilute solutions (0.03 M LiCl). The high absolute value of the efficiency combined with the determination of the optimal membrane morphology makes membrane-based EKEC devices a step closer to practical applications and high-performance membrane design less empirical.

Photoconversion in planar-heterojunction organic photovoltaic cells (OPVs) is limited by a short exciton diffusion length (L(D)) that restricts migration to the dissociating electron donor/acceptor interface. Consequently, bulk heterojunctions are often used to realize high efficiency as these structures reduce the distance an exciton must travel to be dissociated. Here, we present an alternative approach that seeks to directly engineer L(D) by optimizing the intermolecular separation and consequently, the photophysical parameters responsible for excitonic energy transfer. By diluting the electron donor boron subphthalocyanine chloride into a wide-energy-gap host material, we optimize the degree of interaction between donor molecules and observe a ~50% increase in L(D). Using this approach, we construct planar-heterojunction OPVs with a power conversionefficiency of (4.4 ± 0.3)%, > 30% larger than the case of optimized devices containing an undiluted donor layer. The underlying correlation between L(D) and the degree of molecular interaction has wide implications for the design of both OPV active materials and device architectures.

Heavy dye loading and the ability to contain the light within the thin layer (typically ∼12 μm) are the requirement needed for the photoelectrode material in order to enhance the harvesting efficiency of dye solar cell. This can be realized by optimizing the particle size with desirable crystal structure. The paper reports the investigation on the dependency of the dye loading and light scattering on the properties of nanostructured photoelectrode materials by comparing 4 different samples of TiO{sub 2} in the form of nanoparticles and micron-sized TiO{sub 2} aggregates which composed of nanocrystallites. Their properties were evaluated by using scanning electron microscopy, X-ray diffraction and UVVis spectroscopy while the performance of the fabricated test cells were measured using universal photovoltaic test system (UPTS) under 1000 W/cm{sup 2} intensity of radiation. Nano sized particles provide large surface area which allow for greater dye adsorption but have no ability to retain the incident light in the TiO{sub 2} film. In contrast, micron-sized particles in the form of aggregates can generate light scattering allowing the travelling distance of the light to be extended and increasing the interaction between the photons and dye molecules adsorb on TiO{sub 2}nanocrystallites. This resulted in an improvement in the conversionefficiency of the aggregates that demonstrates the close relation between light scattering effect and the structure of the photolectrode film.

Full Text Available The European Union is committed to increasing the use of renewable energies across Europe. One of the ways this is to be done is through the promotion of solar photovoltaics (PV, a method with significant environmental benefits. However, the high costs of electricity generated through PV have constrained the market reach of this option. This paper takes the form of a policy discussion, analyzing the fundamental issues concerning this type of energy, and its place in the European alternative energy market. Furthermore, a scenario is drafted to estimate how efficient solar panels should ideally be to make electricity produced by them cost-competitive with conventional, grid-tied energy sources. The study considers both a conventional scenario and another, with carbon capture costs incorporated into the final electricity prices. It is observed that in order to be competitive with conventional fossil-based electricity, photovoltaic conversionefficiencies should be around 34%. Incorporating carbon costs would further help promote solar PV, making it more price-attractive compared to emission-intensive electricity generation based on fossil fuels. The final part of the paper sheds light on the new developments on European PV, mainly in regards to the 2008 European Commission Climate Change Package, its implications and reactions from the industry.

Detailed model study of THz generation by CO2 laser down-conversion in pure and solid solution crystals GaSe1-xSx is carried out for the first time. Both forward and backward collinear interactions of common (eo-e, oe-e, oe-o, oo-e, ee-o) and original (ee-e, oo-o) types are considered. Possibility of realization, phase matching angles and figure of merits are estimated for line mixing within 9 μm and 10 μm emission bands, as well between them. Dispersion properties of o- and e-wave refractive indices and absorption coefficients for GaSe, GaS and GaSe1-xSx crystals were preliminary measured by THz-TDS, approximated in the equation form and then used in the study. Estimated results are presented in the form of 3-D figures that are suitable for rapid analyses of DFG parameters. The most efficient type of interaction is eo-o type. Optimally doped (x = 0.09-0.13) GaSe1-xSx crystals are from 4 to 5 times more efficient at limit pump intensity than not doped GaSe crystals.

Photosynthesis in plants and cyanobacteria involves two protein-cofactor complexes which are denoted as photosystems (PS), PSII and PSI. These solar-energy converters have powered life on earth for approximately 3 billion years. They facilitate light-driven carbohydrate formation from H(2)O and CO(2), by oxidizing the former and reducing the latter. PSII splits water in a process driven by light. Because all attractive technologies for fuel production driven by solar energy involve water oxidation, recent interest in this process carried out by PSII has increased. In this Account, we describe and apply a rationale for estimating the solar-energy conversionefficiency (eta(SOLAR)) of PSII: the fraction of the incident solar energy absorbed by the antenna pigments and eventually stored in form of chemical products. For PSII at high concentrations, approximately 34% of the incident solar energy is used for creation of the photochemistry-driving excited state, P680*, with an excited-state energy of 1.83 eV. Subsequent electron transfer results in the reduction of a bound quinone (Q(A)) and oxidation of the Tyr(Z) within 1 micros. This radical-pair state is stable against recombination losses for approximately 1 ms. At this level, the maximal eta(SOLAR) is 23%. After the essentially irreversible steps of quinone reduction and water oxidation (the final steps catalyzed by the PSII complex), a maximum of 50% of the excited-state energy is stored in chemical form; eta(SOLAR) can be as high as 16%. Extending our considerations to a photosynthetic organism optimized to use PSII and PSI to drive H(2) production, the theoretical maximum of the solar-energy conversionefficiency would be as high as 10.5%, if all electrons and protons derived from water oxidation were used for H(2) formation. The above performance figures are impressive, but they represent theoretical maxima and do not account for processes in an intact organism that lower these yields, such as light saturation

With growing concern of energy and environmental issues, the combination of plasma and heterogeneous catalysts receives special attention in greenhouse gas conversion, nitrogen fixation and hydrocarbon chemistry. Plasma gas conversion driven by renewable electricity is particularly important for the

The external surface of HZSM-5 zeolite was passivated by liquid siliceous deposition and by acidic sites poisoning with lepidine, respectively. Then methanol-to-hydrocarbons (MTH) reaction was investigated over the above as-prepared catalysts and the dissoluble coke on these used catalysts was analyzed by GC-MS, to study the role of the external surface of HZSM-5 in the catalytic reaction. Comparison with the experi-mental results based on parent ZSM-5 showed that the product distribution of MTH reaction was obviously influenced by the external surface. Evidences were listed as follows:(1) the final product on parent HZSM-5 showed higher aromatic selectivity, lower olefin selectivity, lower ra-tio of C2/C3+aliphatics and higher ratio of C3/C4+aliphatics than the reaction mixture produced by the sole catalysis of acidic sites in HZSM-5 channel;(2) a little of pentamethylbenzene and hexamethylbenzene in the product on parent HZSM-5, was produced via multi-methylation of methylbenzene on the external surface. The above conclusion may also be suitable for MTH reaction over other zeolites with 10-ring channel.

We theoretically investigate the conversionefficiency of spin power to charge power in a normal metal with spin-orbit coupling based on the Green's function method. The normal metal is connected with three leads. A spin current injected in one lead can induce a charge current between another two leads. We find that the conversionefficiency of spin power to charge power is roughly proportional to tSO4 when the spin-orbit coupling tSO is weak, suggesting that the efficiency is limited. Moreover, an increase of temperature may reduce the efficiency. The results may be useful in determining the overall efficiency of a thermoelectric setup based on the longitudinal spin Seebeck effect.

Ethanol is an attractive end product and a versatile feedstock because a widespread market exists for its commercial use as a fuel additive or a potential substitute for gasoline. Currently, ethanol is produced primarily by fermentation of biomass-derived sugars, particularly those containing six carbons, but coproducts 5-carbon sugars and lignin remain unusable. Another major process for commercial production of ethanol is hydration of ethylene over solid acidic catalysts, yet not sustainable considering the depletion of fossil fuels. Catalytic conversion of synthetic gas (CO + H2) could produce ethanol in large quantities. However, the direct catalytic conversion of synthetic gas to ethanol remains challenging, and no commercial process exists as of today although the research has been ongoing for the past 90 years, since such the process suffers from low yield and poor selectivity due to slow kinetics of the initial C-C bond formation and fast chain growth of the C2 intermediates. This Account describes recent developments in an alternative approach for the synthesis of ethanol via synthetic gas. This process is an integrated technology consisting of the coupling of CO with methanol to form dimethyl oxalate and the subsequent hydrogenation to yield ethanol. The byproduct of the second step (methanol) can be separated and used in circulation as the feedstock for the coupling step. The coupling reaction of carbon monoxide for producing dimethyl oxalate takes place under moderate reaction conditions with high selectivity (∼95%), which ideally leads to a self-closing, nonwaste, catalytic cycling process. This Account also summarizes the progress on the development of copper-based catalysts for the hydrogenation reaction with remarkable efficiencies and stability. The unique lamellar structure and the cooperative effect between surface Cu(0) and Cu(+) species are responsible for the activity of the catalyst with high yield of ethanol (∼91%). The understanding of

A series of P/HZSM-5 catalysts prepared by impregnation method were used for ethanol conversion to lower olefins.The catalysts were characterized by X-ray diffraction(XRD),NH3-temperature-programmed desorption(NH3-TPD)and N2 adsorption-desorption measurements.It was found that the P/HZSM-5 catalysts showed high activity and selectivity toward light olefins.The selectivities of propylene and butylene can be improved with the introduction of phosphorus(P).When the content of P reached 3.0 wt%,more than 18.9% propylene in the gaseous products was obtained over the P/HZSM-5 catalyst at 450 ℃.The introduction of P modified the strong Br()nsted acid sites of the original HZSM-5 catalysts and P/HZSM-5 catalysts could resist coke formation and showed good stability.

The Bioenergy Feedstock Development Program, Environmental Sciences Division, Oak Ridge National Laboratory is developing poplars (Populus species and hybrids) as sources of renewable energy, i.e., ethanol. Notable increases in adaptability, volume productivity, and pest/stress resistance have been achieved via classical selection and breeding and intensified cultural practices. Significant advances have also been made in the efficiencies of harvesting and handling systems. Given these and anticipated accomplishments, program leaders are considering shifting some attention to genetically modifying feedstock physical and chemical properties, so as to improve the efficiency with which feedstocks can be converted to ethanol. This report provides an in-depth review and synthesis of opportunities for and feasibilities of genetically modifying feedstock qualities via classical selection and breeding, marker-aided selection and breeding, and genetic transformation. Information was collected by analysis of the literature, with emphasis on that published since 1995, and interviews with prominent scientists, breeders, and growers. Poplar research is well advanced, and literature is abundant. The report therefore primarily reflects advances in poplars, but data from other species, particularly other shortrotation hardwoods, are incorporated to fill gaps. An executive summary and recommendations for research, development, and technology transfer are provided immediately after the table of contents. The first major section of the report describes processes most likely to be used for conversion of poplar biomass to ethanol, the various physical and chemical properties of poplar feedstocks, and how such properties are expected to affect process efficiency. The need is stressed for improved understanding of the impact of change on both overall process and individual process step efficiencies. The second part documents advances in trait measurement instrumentation and methodology

Here, we present routes to increase CO2 conversion into CO using an atmospheric pressure dielectric-barrier discharge. The change in conversion as a function of simple plasma parameters, such as power, flow rate, but also frequency, on-and-off power pulse, thickness and the chemical nature of the dielectric, wall and gas temperature, are described. By means of an in-depth electrical characterization of the discharge (effective plasma voltage, dielectric voltage, plasma current, number and lifetime of the microdischarges), combined with infrared analysis of the walls of the reactor, optical emission spectroscopy for the gas temperature, and mass spectrometry for the CO2 conversion, we propose a global interpretation of the effect of all the experimental parameters on the conversion and efficiency of the reaction.

The Short Rotation Woody Crop Program (SRWCP), Department of Energy, is developing woody plant species as sources of renewable energy. Much progress has been made in identifying useful species, and testing site adaptability, stand densities, coppicing abilities, rotation lengths, and harvesting systems. Conventional plant breeding and intensive cultural practices have been used to increase above-ground biomass yields. Given these and foreseeable accomplishments, program leaders are now shifting attention to prospects for altering biomass physical and chemical characteristics, and to ways for improving the efficiency with which biomass can be converted to gaseous and liquid fuels. This report provides a review and synthesis of literature concerning the quantity and quality of such characteristics and constituents, and opportunities for manipulating them via conventional selection and breeding and/or molecular biology. Species now used by SRWCP are emphasized, with supporting information drawn from others as needed. Little information was found on silver maple (Acer saccharinum), but general comparisons (Isenberg 1981) suggest composition and behavior similar to those of the other species. Where possible, conclusions concerning means for and feasibility of manipulation are given, along with expected impacts on conversionefficiency. Information is also provided on relationships to other traits, genotype X environment interactions, and potential trade-offs or limitations. Biomass productivity per se is not addressed, except in terms of effects that may by caused by changes in constituent quality and/or quantity. Such effects are noted to the extent they are known or can be estimated. Likely impacts of changes, however effected, on suitability or other uses, e.g., pulp and paper manufacture, are notes. 311 refs., 4 figs., 9 tabs.

Production of lactic acid from glycerol is a cascade catalytic procedure using multifunctional catalysts combined with oxidative and acidic catalytic sites. Therefore, a series of silver-exchanged phosphomolybdic acid catalysts (AgxH3‑xPMo12O40, x = 1 ~ 3, abbreviated as AgxPMo) was designed and applied in glycerol oxidation with O2 as an oxidant to produce lactic acid (LA) without adding any base. Among all, total silver exchanged phosphomolybdic acid (Ag3PMo) was found to be the most active one with LA selectivity of 93% at 99% conversion under mild conditions of 5 h at 60 °C. The exceptionally high efficiency was contributed to the generation of strong Lewis acid sites, enhanced redox potentials and water-tolerance. More importantly, Ag3PMo was tolerant in crude glycerol from biodiesel production. And the reaction mechanism was also discussed. Meanwhile, Ag3PMo acted as a heterogeneous catalyst for 12 recycles without loss of activity.

Incorporating protozoa into population models (from simple predator-prey explorations to complex food web simulations) is of conceptual, ecological, and economic importance. From theoretical and empirical perspectives, we expose unappreciated complexity in the traditional predator-prey model structure and provide a parsimonious solution, especially for protistologists. We focus on how prey abundance alters two key components of models: predator conversionefficiency (e, the proportion of prey converted to predator, before mortality loss) and predator mortality (δ, the portion of the population lost though death). Using a well-established model system (Paramecium and Didinium), we collect data to parameterize a range of existing and novel population models that differ in the functional forms of e and δ. We then compare model simulations to an empirically obtained time-series of predator-prey population dynamics. The analysis indicates that prey-dependent e and δ should be considered when structuring population models and that both prey and predator biomass also vary with prey abundance. Both of these impact the ability of the model to predict population dynamics and, therefore, should be included in theoretical model evaluations and assessment of ecosystem dynamics associated with biomass flux.

Full Text Available In this article we present two logics of water efficiency: that of the Water Footprint and that of mango smallholder farmers on the desert coast of Peru (in Motupe. We do so in order to explore how both can learn from each other and to discuss what happens when the two logics meet. Rather than treating the Water Footprint as scientific, in the sense that it is separate from traditions or politics, and Motupe poza irrigation as cultural and, therefore, thick with local beliefs and superstitions, we describe both as consisting of intricate entanglements of knowledge and culture. This produces a more or less level playing field for the two water logics to meet and for proponents of each to enter into a conversation with one another; allowing furthermore for the identification of what Water Footprint inventors and promotors can learn from poza irrigators, and vice versa. The article concludes that important water wisdom may get lost when the Water Footprint logic becomes dominant, as is currently about to happen in Peru.

Full Text Available Titania powder (P25 was dispersed by bead-milling breakdown method, and the dispersivity of TiO2 was controlled by adjusting the mean secondary TiO2 particle size to 45, 56, and 75 nm by changing the dispersion solvent blend ratio of ethanol and terpineol. The transparency of the coated layer increased when the particle size of TiO2 aggregates became smaller than 100 nm. Although the transparency was significantly different according to differences in the size of nanocrystallyne-TiO2 aggregates, the resulting photovoltaic (PV effect of a dye-sensitized solar cell (DSSC was not significantly different between the different aggregate sizes. A double layer structure (transparent TiO2 layer/opaque TiO2 layer was adopted to improve the PV effect, which resulted in an improvement of the photocurrent and conversionefficiency of 13.2% and 11.1%, respectively, from that for the DSSCs with single-layered TiO2 electrodes.

Frequency conversion of laser beams, based on stimulated Raman scattering (SRS) is an appealing technique for generating radiation at new wavelengths. Here, we investigated experimentally the SRS due to a single pass of a collimated frequency-doubled Nd:YAG laser beam (532 nm) through a saturated aqueous solution of sodium nitrate (NaNO{sub 3}), filling a 50 cm long cell. These experiments resulted in simultaneous generation of 1st (564 nm) and 2nd (599 nm) Stokes beams, corresponding to the symmetric stretching mode of the nitrate ion, ν{sub 1}(NO{sub 3}{sup −}), with 40 and 12 mJ/pulse maximal converted energies, equivalent to 12% and 4% efficiencies, respectively, for a 340 mJ/pulse pump energy. The results indicate that the pump and SRS beams were thermally defocused and that four-wave mixing was responsible for the second order Stokes process onset.

Dielectric elastomer generators (DEGs), which follow the physics of variable capacitors and harvest electric energy from mechanical work, have attracted intensive attention over the past decade. The lack of ideal dielectric elastomers, after nearly two decades of research, has become the bottleneck for DEGs' practical applications. Here, we fabricated a series of polyurethane-based ternary composites and estimated their potential as DEGs to harvest electric energy for the first time. Thermoplastic polyurethane (PU) with high relative permittivity (∼8) was chosen as the elastic matrix. Barium titanate (BT) nanoparticles and dibutyl phthalate (DBP) plasticizers, which were selected to improve the permittivity and mechanical properties, respectively, were blended into the PU matrix. As compared to pristine PU, the resultant ternary composite films fabricated through a solution casting approach showed enhanced permittivity, remarkably reduced elastic modulus, and relatively good electrical breakdown strength, dielectric loss, and strain at break. Most importantly, the harvested energy density of PU was significantly enhanced when blended with BT and DBP. A composite film containing 25 phr of BT and 60 phr of DBP with the harvested energy density of 1.71 mJ/cm(3) was achieved, which is about 4 times greater than that of pure PU and 8 times greater than that of VHB adhesives. Remarkably improved conversionefficiency of mechano-electric energy was also obtained via cofilling BT and DBP into PU. The results shown in this work strongly suggest compositing is a very promising way to provide better dielectric elastomer candidates for forthcoming practical DEGs.

Energy production is inextricably linked to national security and poses the danger of altering the environment in potentially catastrophic ways. There is no greater problem than sustainable energy production. Our purpose was to attack this problem by examining processes, technology, and science needed for recycling CO{sub 2} back into transportation fuels. This approach can be thought of as 'bio-inspired' as nature employs the same basic inputs, CO{sub 2}/energy/water, to produce biomass. We addressed two key deficiencies apparent in current efforts. First, a detailed process analysis comparing the potential for chemical and conventional engineering methods to provide a route for the conversion of CO{sub 2} and water to fuel has been completed. No apparent 'showstoppers' are apparent in the synthetic route. Opportunities to improve current processes have also been identified and examined. Second, we have also specifically addressed the fundamental science of the direct production of methanol from CO{sub 2} using H{sub 2} as a reductant.

Anodized and annealed titanium oxide nanotubes show enhanced photo activity and can be used as photo anodes for water electrolysis in hydrogen generation. Application of an external potential to the photo anode is required for enhancement of the photocurrent. This additional electrical energy input complicates the photo conversionefficiency calculation. In this investigation, the photo-electrochemical behavior of anodized titanium oxide nanotubular arrays have been characterized in various electrolytes. Increase in the applied potential increased the photocurrent under illumination with visible light. A simple experimental method for calculating the photo conversionefficiency has been proposed. According to this method, the potential difference between the photo anode and cathode is measured with and without light illumination. The product of the photocurrent and the increase in potential due to light irradiation is considered as the net power output. The photocurrent and the conversionefficiency increased with increase in the pH of the electrolyte. TiO 2 nanotubular arrays annealed at 350 °C for 6 h in nitrogen atmosphere showed a maximum photo conversionefficiency of ∼4% in 1 M KOH electrolyte and ∼3% in 3.5 wt.% sodium chloride solution. The results indicate that nanotubular TiO 2 can be potentially used for the photo electrolysis of seawater to generate hydrogen.

The Bremsstrahlung and K-shell emission from 1 mm x 1 mm x 1 mm planar targets irradiated by a short-pulse 3 x 10{sup 18}-8 x 10{sup 19} W/cm{sup 2} laser were measured. The Bremsstrahlung was measured using a filter stack spectrometer with spectral discrimination up to 500 keV. K-shell emission was measured using a single photon counting charge coupled device (CCD). From Monte Carlo modeling of the target emission, conversionefficiencies into 1-3 MeV electrons of 3-12%, representing 20-40% total conversionefficiencies were inferred for intensities up to 8 x 10{sup 19} W/cm{sup 2}. Comparisons to scaling laws using synthetic energy spectra generated from the intensity distribution of the focal spot imply slope temperatures less than the ponderomotive potential of the laser. Resistive transport effects may result in potentials of a few hundred kV in the first few tens of microns in the target. This would lead to higher total conversionefficiencies than inferred from Monte Carlo modeling but lower conversionefficiencies into 1-3 MeV electrons.

This report measures the actions performed in 2006 and the actions planned for 2007 within the framework of the project Efficient Energy Conversion in the Pulp and Paper Industry. In addition to the data reconciliation models of the steam and condensate networks and of the process of Borregaard Schweiz AG, process models have been developed with the goal of defining the heat requirements of the process. The combination of utility system data reconciliation with the process models allows to considerably reduce the need for detailed process modelling and for on-site data collection and measurement. A systematic definition of the hot and cold streams in the process has been developed in order to compute the minimum energy requirement of the process. The process requirements have been defined using the dual representation concept where the energy requirement of the process unit operations are systematically analysed from their thermodynamic requirement and the way they are satisfied by the technology that implements the operation. Corresponding to the same energy requirement but realised with different temperature allows on one hand to define the exergy efficiency of the heat transfer system in each of the process unit operations and to identify possible energy savings by heat exchange in the system. The analysis has been completed by the definition of the possible energy recovery from waste streams. The minimum energy requirement of the process using the different requirement representation has been realised and the analysis of the energy savings opportunities is now under preparation. This new step will first concern the definition of the utility system integration and the systematic analysis of the energy savings opportunities followed by the techno-economic evaluation of the most profitable energy savings options in the process. The national and international collaborations constitute also an important part of this project. The project is done in close

There are two commonly-used approaches to modeling the future supply of mineral resources. One is to estimate reserves and compare the result to extraction rates, and the other is to project from historical time series of extraction rates. Perceptions of abundant oil supplies in the Middle East and abundant coal supplies in the United States are based on the former approach. In both of these cases, an approach based on historical production series results in a much smaller resource estimate than aggregate reserve numbers. This difference is not systematic; natural gas production in the United States shows a strong increasing trend even though modest reserve estimates have resulted in three decades of worry about the gas supply. The implication of a future decline in Middle East oil production is that the market for transportation fuels is facing major changes, and that alternative fuels should be analyzed in this light. Because the U.S. holds very large coal reserves, synthesizing liquid hydrocarbons from coal has been suggested as an alternative fuel supply. To assess the potential of this process, one has to look at both the resource base and the net efficiency. The three states with the largest coal production declines in the 1996 to 2006 period are among the top 5 coal reserve holders, suggesting that gross coal reserves are a poor indicator of future production. Of the three categories of coal reserves reported by the U.S. Energy Information Administration, reserves at existing mines is the narrowest category and is approximately the equivalent of proved developed oil reserves. By this measure, Wyoming has the largest coal reserves in the U.S., and it accounted for all of U.S. coal production growth over the 1996 to 2006 time period. In Chapter 2, multi-cycle Hubbert curve analysis of historical data of coal production from 1850 to 2007 demonstrates that U.S. anthracite and bituminous coal are past their production peak. This result contradicts estimates based

This report contains the abstracts of papers presented at a workshop on polycyclic aromatic hydrocarbons (PAH) such as those produced by coal conversion technologies. Their often carcinogenic nature imposes the obligation of providing adequate protection and measurement devices for workers and for the general public. The primary questions are as follows: What should be measured. Where and how should it be measured. What are the maximum permissible concentrations. This workshop and future workshops are intended to bring these problems into better focus and to help establish a consensus on what needs to be done in order to provide a dosimetry effort that will ensure the adequate protection of personnel. There were 32 attendees of this one-day meeting. The papers and discussions included current industrial hygiene practices, the development of government agency guidelines for worker protection, and a wide range of analytical techniques for PAH detection, some of which are still in the research stage and are unproven. The workshop was held at ORNL on February 26, 1976.

Full Text Available The loading and removal efficiency of 16 US EPA polycyclic aromatic hydrocarbons (PAHs were examined in an inverted A2/O wastewater treatment plant (WWTP located in an urban area in China. The total PAH concentrations were 554.3 to 723.2 ng/L in the influent and 189.6 to 262.7 ng/L in the effluent. The removal efficiencies of ∑PAHs in the dissolved phase ranged from 63 to 69%, with the highest observed in naphthalene (80% removal. Concentration and distribution of PAHs revealed that the higher molecular weight PAHs became more concentrated with treatment in both the dissolved phase and the dewatered sludge. The sharpest reduction was observed during the pretreatment and the biological phase. Noncarcinogenic risk, carcinogenic risk, and total health risk of PAHs found in the effluent and sewage sludge were also assessed. The effluent BaP toxic equivalent quantities (TEQBaP were above, or far above, standards in countries. The potential toxicities of PAHs in sewage effluent were approximately 10 to 15 times higher than the acceptable risk level in China. The health risk associated with the sewage sludge also exceeded international recommended levels and was mainly contributed from seven carcinogenic PAHs. Given that WWTP effluent is a major PAH contributor to surface water bodies in China and better reduction efficiencies are achievable, the present study highlights the possibility of utilizing WWTPs for restoring water quality in riverine and coastal regions heavily impacted by PAHs contamination.

Dye sensitized solar cells (DSSCs) with an innovative design involving controlled-morphology vertically aligned (VA) ZnO nanowires within mesoporous TiO2 structures with ultrahigh surface area for implementation as photoanodes are herein reported. Although TiO2 nanostructures exhibit excellent power conversionefficiency, the electron transport rate is low owing to low electron mobility. To overcome this, ZnO nanowires with high electron mobility have been investigated as potential candidates for photoanodes. However, the power conversionefficiency of ZnO nanowires is still lower than that of TiO2 owing to their low internal surface area. Consequently, in this work, vertical growth of ZnO nanowires within mesoporous TiO2 structures is carried out to increase their solar power conversionefficiency. The photovoltaic performance of solar cells using ZnO nanowires, mesoporous TiO2, and TiO2/ZnO hybrid structures are compared. The VA TiO2/ZnO hybrid structures are found to provide direct electron transfer compared with the tortuous pathway of zero-dimensional nanostructures, resulting in an increased conversionefficiency. It is demonstrated that the light scattering of the photoanode film is increased and electron recombination is decreased when an appropriate amount of mesoporous TiO2 is used as a substrate for ZnO nanowires. The DSSC fabricated with the TiO2/ZnO hybrid photoanode prepared with 15.8 wt. % TiO2 showed the highest conversionefficiency of 7.30%, approximately 5%, 18%, and 40% higher than that of DSSCs fabricated with 3.99 wt. % TiO2, pure TiO2, and pure ZnO photoanodes, respectively.

Dye sensitized solar cells (DSSCs) with an innovative design involving controlled-morphology vertically aligned (VA) ZnO nanowires within mesoporous TiO{sub 2} structures with ultrahigh surface area for implementation as photoanodes are herein reported. Although TiO{sub 2} nanostructures exhibit excellent power conversionefficiency, the electron transport rate is low owing to low electron mobility. To overcome this, ZnO nanowires with high electron mobility have been investigated as potential candidates for photoanodes. However, the power conversionefficiency of ZnO nanowires is still lower than that of TiO{sub 2} owing to their low internal surface area. Consequently, in this work, vertical growth of ZnO nanowires within mesoporous TiO{sub 2} structures is carried out to increase their solar power conversionefficiency. The photovoltaic performance of solar cells using ZnO nanowires, mesoporous TiO{sub 2}, and TiO{sub 2}/ZnO hybrid structures are compared. The VA TiO{sub 2}/ZnO hybrid structures are found to provide direct electron transfer compared with the tortuous pathway of zero-dimensional nanostructures, resulting in an increased conversionefficiency. It is demonstrated that the light scattering of the photoanode film is increased and electron recombination is decreased when an appropriate amount of mesoporous TiO{sub 2} is used as a substrate for ZnO nanowires. The DSSC fabricated with the TiO{sub 2}/ZnO hybrid photoanode prepared with 15.8 wt. % TiO{sub 2} showed the highest conversionefficiency of 7.30%, approximately 5%, 18%, and 40% higher than that of DSSCs fabricated with 3.99 wt. % TiO{sub 2}, pure TiO{sub 2}, and pure ZnO photoanodes, respectively.

The energy conversionefficiency of gas-steam turbine cycles was investigated for selected combined cycle power plants. Results indicate that it is possible for combined cycle gas-steam turbine power plants to have efficiencies several point higher than conventional steam plants. Induction of low pressure steam into the steam turbine is shown to improve the plant efficiency. Post firing of the boiler of a high temperature combined cycle plant is found to increase net power but to worsen efficiency. A gas turbine pressure ratio of 12 to 1 was found to be close to optimum at all gas turbine inlet temperatures that were studied. The coal using combined cycle plant with an integrated low-Btu gasifier was calculated to have a plant efficiency of 43.6%, a capitalization of $497/kW, and a cost of electricity of 6.75 mills/MJ (24.3 mills/kwh). This combined cycle plant should be considered for base load power generation.

A wide variety of charge carrier dynamics, such as transport, separation, and extraction, occur at the interfaces of planar heterojunction solar cells. Such factors can affect the overall device performance. Therefore, understanding the buried interfacial molecular structure in various devices and the correlation between interfacial structure and function has become increasingly important. Current characterization techniques for thin films such as X-ray diffraction, cross section scanning electronmicroscopy, and UV-visible absorption spectroscopy are unable to provide the needed molecular structural information at buried interfaces. In this study, by controlling the structure of the hole transport layer (HTL) in a perovskite solar cell and applying a surface/interface-sensitive nonlinear vibrational spectroscopic technique (sum frequency generation vibrational spectroscopy (SFG)), we successfully probed the molecular structure at the buried interface and correlated its structural characteristics to solar cell performance. Here, an edge-on (normal to the interface) polythiophene (PT) interfacial molecular orientation at the buried perovskite (photoactive layer)/PT (HTL) interface showed more than two times the power conversionefficiency (PCE) of a lying down (tangential) PT interfacial orientation. The difference in interfacial molecular structure was achieved by altering the alkyl side chain length of the PT derivatives, where PT with a shorter alkyl side chain showed an edge-on interfacial orientation with a higher PCE than that of PT with a longer alkyl side chain. With similar band gap alignment and bulk structure within the PT layer, it is believed that the interfacial molecular structural variation (i.e., the orientation difference) of the various PT derivatives is the underlying cause of the difference in perovskite solar cell PCE.

The down conversion (DC) material ZnO: Eu3+, Dy3+ are synthesized by precipitation method and used to prepare the photo anode of dye-sensitized solar cells (DSSCs). The effects of down conversion material on the photoelectric performance of the DSSC were characterized by the X-ray diffraction (XRD), photoluminescence (PL), scanning electron microscope (SEM), current-voltage (I-V) curve, incident-photon-to-current conversionefficiency (IPCE) and UV-vis-NIR absorption spectroscopy. In this paper, Eu3+, Dy3+ codoped ZnO excited by from UV to blue light converts blue to red light emission, corresponding to the absorption region of the dye (N719). At the concentration 1.75% of ZnO: Eu3+, Dy3+ (weight ratio of DC to TiO2), the short-circuit current density and conversionefficiency of the DSSCs reached to the optimal values: 8.92 mA cm-2 and 4.48%, about 212% and 245% higher than with pure TiO2 and about 91.4% and 105% higher than with TiO2/graphene (G) structure, respectively. The research result reveals that the application of DC material can improve the efficiency of DSSCs.

We demonstrate enhancement of FWM wavelength conversion of a 40 Gbps signal in a reverse-biased p-i-n junction silicon waveguide. A conversionefficiency of −4.6 dB enables a conversion power penalty as low as 0.2 dB....

The three foundational elements that determine mobile source energy use and tailpipe carbon dioxide (CO2) emissions are the tractive energy requirements of the vehicle, the on-cycle energy conversionefficiency of the propulsion system, and the energy source. The tractive energy requirements are determined by the vehicle's mass, aerodynamic drag, tire rolling resistance, and parasitic drag. Oncycle energy conversion of the propulsion system is dictated by the tractive efficiency, non-tractive energy use, kinetic energy recovery, and parasitic losses. The energy source determines the mobile source CO2 emissions. For current vehicles, tractive energy requirements and overall energy conversionefficiency are readily available from the decomposition of test data. For future applications, plausible levels of mass reduction, aerodynamic drag improvements, and tire rolling resistance can be transposed into the tractive energy domain. Similarly, by combining thermodynamic, mechanical efficiency, and kinetic energy recovery fundamentals with logical proxies, achievable levels of energy conversionefficiency can be established to allow for the evaluation of future powertrain requirements. Combining the plausible levels of tractive energy and on-cycle efficiency provides a means to compute sustainable vehicle and propulsion system scenarios that can achieve future regulations. Using these principles, the regulations established in the United States (U.S.) for fuel consumption and CO2 emissions are evaluated. Fleet-level scenarios are generated and compared to the technology deployment assumptions made during rule-making. When compared to the rule-making assumptions, the results indicate that a greater level of advanced vehicle and propulsion system technology deployment will be required to achieve the model year 2025 U.S. standards for fuel economy and CO2 emissions.

Feeding a growing population while minimizing environmental degradation is a global challenge requiring thoroughly rethinking food production and consumption. Dietary choices control food availability and natural resource demands. In particular, reducing or avoiding consumption of low production efficiency animal-based products can spare resources that can then yield more food. In quantifying the potential food gains of specific dietary shifts, most earlier research focused on calories, with less attention to other important nutrients, notably protein. Moreover, despite the well-known environmental burdens of livestock, only a handful of national level feed-to-food conversionefficiency estimates of dairy, beef, poultry, pork, and eggs exist. Yet such high level estimates are essential for reducing diet related environmental impacts and identifying optimal food gain paths. Here we quantify caloric and protein conversionefficiencies for US livestock categories. We then use these efficiencies to calculate the food availability gains expected from replacing beef in the US diet with poultry, a more efficient meat, and a plant-based alternative. Averaged over all categories, caloric and protein efficiencies are 7%-8%. At 3% in both metrics, beef is by far the least efficient. We find that reallocating the agricultural land used for beef feed to poultry feed production can meet the caloric and protein demands of ≈120 and ≈140 million additional people consuming the mean American diet, respectively, roughly 40% of current US population.

Polycyclic aromatic hydrocarbons are a class of molecules composed of multiple, bonded benzene rings. As PAHS are believed to be present on Mars, positive confirmation of their presence on Mars is highly desirable. To extract PAHS, which have low volatility, a fluid extraction method is ideal, and one that does not utilize organic solvents is especially ideal for in situ instrumental analysis. The use of water as a solvent, which at subcritical pressures and temperatures is relatively non-Polar, has significant potential. As SCWE instruments have not yet been commercialized, all instruments are individually-built research prototypes: thus, initial efforts were intended to determine if extraction efficiencies on the JPL-built laboratory-scale SCWE instrument are comparable to differing designs built elsewhere. Samples of soil with certified reference concentrations of PAHs were extracted using SCWE as well as conventional Soxhlet extraction. Continuation of the work would involve extractions on JPL'S newer, portable SCWE instrument prototype to determine its efficiency in extracting PAHs.

National Aeronautics and Space Administration — This SBIR Phase I proposal responds to topic S3.03 of the 2010 NASA SBIR solicitation, for Power Generation and Conversion. Thermoelectric devices offer a simple and...

Wavelength conversion based on four-wave mixing is theoretically compared in silicon micro-ring resonators and nanowires under the effect of nonlinear loss. The impact of the bus waveguide length and MRR position are also quantified....

A method for circuit-parametric analysis of the efficiency of the heat-and-power system of the energy complexes at gas and natural-gas condensate processing plants is proposed. An energy complex of an alternative structure with an independent source of thermal and electric energy integrated into the production line has been developed. The energy carriers are produced accompanied by recovery of the secondary energy resources, waste, and effluents. Using the developed information-analytical software, multicriterion assessment of the efficiency of the alternative energy complexes and its systems based on independent energy sources of the combined-cycle cogeneration plant type has been performed for the gas processing plant in Astrakhan and the most effective equipment composition variant has been determined. The effect of the basic technical and economic factors on the economic efficiency has been established. The investments in construction of the power- and water-supply system within the plant's energy complex pay off in 8-9 years.

We report on efficient carrier-to-exciton conversion and planar electroluminescence from tunnel diodes based on a metal-insulator-semiconductor (MIS) van der Waals heterostack consisting of few-layer graphene (FLG), hexagonal boron nitride (hBN), and monolayer tungsten disulfide (WS2). These devices exhibit excitonic electroluminescence with extremely low threshold current density of a few pA·μm(-2), which is several orders of magnitude lower compared to the previously reported values for the best planar EL devices. Using a reference dye, we estimate the EL quantum efficiency to be ∼1% at low current density limit, which is of the same order of magnitude as photoluminescence quantum yield at the equivalent excitation rate. Our observations reveal that the efficiency of our devices is not limited by carrier-to-exciton conversionefficiency but by the inherent exciton-to-photon yield of the material. The device characteristics indicate that the light emission is triggered by injection of hot minority carriers (holes) to n-doped WS2 by Fowler-Nordheim tunneling and that hBN serves as an efficient hole-transport and electron-blocking layer. Our findings offer insight into the intelligent design of van der Waals heterostructures and avenues for realizing efficient excitonic devices.

This fact sheet describes how the SJ3 solar cell was invented, explains how the technology works, and why it won an R&D 100 Award. Based on NREL and Solar Junction technology, the commercial SJ3 concentrator solar cell - with 43.5% conversionefficiency at 418 suns - uses a lattice-matched multijunction architecture that has near-term potential for cells with {approx}50% efficiency. Multijunction solar cells have higher conversionefficiencies than any other type of solar cell. But developers of utility-scale and space applications crave even better efficiencies at lower costs to be both cost-effective and able to meet the demand for power. The SJ3 multijunction cell, developed by Solar Junction with assistance from foundational technological advances by the National Renewable Energy Laboratory, has the highest efficiency to date - almost 2% absolute more than the current industry standard multijunction cell-yet at a comparable cost. So what did it take to create this cell having 43.5% efficiency at 418-sun concentration? A combination of materials with carefully designed properties, a manufacturing technique allowing precise control, and an optimized device design.

This report was developed as part of the U.S. Department of Energy’s Bioenergy Technologies Office’s efforts to enable the development of technologies for the production of infrastructure-compatible, cost-competitive liquid hydrocarbon fuels from biomass. Specifically, this report details two conceptual designs based on projected product yields and quality improvements via catalyst development and process integration. It is expected that these research improvements will be made within the 2022 timeframe. The two conversion pathways detailed are (1) in situ and (2) ex situ upgrading of vapors produced from the fast pyrolysis of biomass. While the base case conceptual designs and underlying assumptions outline performance metrics for feasibility, it should be noted that these are only two of many other possibilities in this area of research. Other promising process design options emerging from the research will be considered for future techno-economic analysis. Both the in situ and ex situ conceptual designs, using the underlying assumptions, project MFSPs of approximately $3.5/gallon gasoline equivalent (GGE). The performance assumptions for the ex situ process were more aggressive with higher distillate (diesel-range) products. This was based on an assumption that more favorable reaction chemistry (such as coupling) can be made possible in a separate reactor where, unlike in an in situ upgrading reactor, one does not have to deal with catalyst mixing with biomass char and ash, which pose challenges to catalyst performance and maintenance. Natural gas was used for hydrogen production, but only when off gases from the process was not sufficient to meet the needs; natural gas consumption is insignificant in both the in situ and ex situ base cases. Heat produced from the burning of char, coke, and off-gases allows for the production of surplus electricity which is sold to the grid allowing a reduction of approximately 5¢/GGE in the MFSP.

We report a modified technique for the fabrication of zinc-diffused channel waveguides using z-cut electric-field periodically poled LiNbO3. Unlike previous work, the diffusion was carried out using metallic zinc at atmospheric pressure. By optimizing the thermal diffusion parameters, channel waveguides that preserve the existing periodically poled domain structures, support both TE and TM modes, and enhance photorefractive damage resistance were obtained. Nonlinear characterisation of the channel waveguides was investigated via second harmonic generation of a 1552nm laser with a maximum conversionefficiency of 59%W-1cm-2 at 14.6ºC. Using a pulsed source a second harmonic conversionefficiency of 81% was achieved.

@@ 40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversionefficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.

We report on nonlinear frequency conversion from the telecom range via second harmonic generation (SHG) and third harmonic generation (THG) in suspended gallium nitride slab photonic crystal (PhC) cavities on silicon, under continuous-wave resonant excitation. Optimized two-dimensional PhC cavities with augmented far-field coupling have been characterized with quality factors as high as 4.4$\\times10^{4}$, approaching the computed theoretical values. The strong enhancement in light confinement has enabled efficient SHG, achieving normalized conversionefficiency of 2.4$\\times10^{-3}$ $W^{-1}$, as well as simultaneous THG. SHG emission power of up to 0.74 nW has been detected without saturation. The results herein validate the suitability of gallium nitride for integrated nonlinear optical processing.

An all-optical approach to laser-proton acceleration enhancement is investigated using the simplest of target designs to demonstrate application-relevant levels of energy conversionefficiency between laser and protons. Controlled deposition of laser energy, in the form of a double-pulse temporal envelope, is investigated in combination with thin foil targets in which recirculation of laser-accelerated electrons can lead to optimal conditions for coupling laser drive energy into the proton beam. This approach is shown to deliver a substantial enhancement in the coupling of laser energy to 5-30 MeV protons, compared to single pulse irradiation, reaching a record high 15% conversionefficiency with a temporal separation of 1 ps between the two pulses and a 5 μm-thick Au foil. A 1D simulation code is used to support and explain the origin of the observation of an optimum pulse separation of ˜1 ps.

An all-optical approach to laser-proton acceleration enhancement is investigated using the simplest of target designs to demonstrate application-relevant levels of energy conversionefficiency between laser and protons. Controlled deposition of laser energy, in the form of a double-pulse temporal envelope, is investigated in combination with thin foil targets in which recirculation of laser-accelerated electrons can lead to optimal conditions for coupling laser drive energy into the proton beam. This approach is shown to deliver a substantial enhancement in the coupling of laser energy to 5–30 MeV protons, compared to single pulse irradiation, reaching a record high 15% conversionefficiency with a temporal separation of 1 ps between the two pulses and a 5 μm-thick Au foil. A 1D simulation code is used to support and explain the origin of the observation of an optimum pulse separation of ∼1 ps.

The solar-to-electric power-conversionefficiency ({eta}) of dye-sensitized solar cells can be greatly enhanced by integrating a mesoporous, nanoparticle-based, 1D photonic crystal as a coherent scattering layer in the device. The photogenerated current is greatly improved without altering the open-circuit voltage of the cell, while keeping the transparency of the cell intact. Improved average {eta} values between 15% and 30% are attained. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

The thermoelectric conversionefficiency of a GaP doped SiGe alloy is improved about 30 percent by annealing the alloy at a temperature above the melting point of the alloy, preferably stepwise from 1200 C to 1275 C in air to form large grains having a size over 50 microns and to form a GeGaP rich phase and a silicon rich phase containing SiP and SiO2 particles.

Pneumonia - hydrocarbon ... Coughing Fever Shortness of breath Smell of a hydrocarbon product on the breath Stupor (decreased level of ... Most children who drink or inhale hydrocarbon products and develop ... hydrocarbons may lead to rapid respiratory failure and death.

Aerobically grown enrichment cultures derived from hydrocarbon- contaminated seawater and freshwater sediments were generated by growth on crude oil as sole carbon source. Both cultures displayed a high rate of degradation for a wide range of hydrocarbon compounds. The bacterial species composition

A light emitting apparatus includes a source of light for emitting light; a down conversion material receiving the emitted light, and converting the emitted light into transmitted light and backward transmitted light; and an optic device configured to receive the backward transmitted light and transfer the backward transmitted light outside of the optic device. The source of light is a semiconductor light emitting diode, a laser diode (LD), or a resonant cavity light emitting diode (RCLED). The down conversion material includes one of phosphor or other material for absorbing light in one spectral region and emitting light in another spectral region. The optic device, or lens, includes light transmissive material.

This patent describes a catalyst composition. It comprises: a modified Y zeolite having a unit cell size below about 24.45 {angstrom}, a degree of crystallinity which is at least retained at increasing SiO{sub 2}/Al{sub 2}O{sub 3} molar ratios, a SiO{sub 2}/Al{sub 2}O{sub 3} molar ratio between about 8 to about 15, a water adsorption capacity at (25{degree}C and a p/p{sub {ital o}} value of 0.2) of between about 10--15% by weight of modified zeolite and a pore volume of at lest about 0.25 ml/g. Between about 10 to about 40% of the total pore volume is made up of pores having a diameter of at least about 8 nm; an amorphous cracking component comprising a silica-alumina containing 50--95% by weight of silica; a binder comprising alumina; from about 0.05 to about 10 percent by weight of nickel and from about 2 to about 40 percent by weight of tungsten, calculated as metals per 100 parts by weight of total catalyst. The modified Y zeolite and amorphous cracking component comprises about 60--85% by weight of the total catalyst, the binder comprises about 15--40% by weight of the total catalyst and the amount of modified Y zeolite ranges between about 10--75% of the combined amount of modified Y zeolite and amorphous cracking component.

We consider a recently proposed gyroscopic device for conversion of mechanical ocean wave energy to electrical energy. Two models of the device derived from standard engineering mechanics from the literature are analysed, and a model is derived from analytical mechanics considerations. From...

Ligands for aryl hydrocarbon receptor (AHR), such as dioxins, are highly toxic. One such ligand, TCDD, was found to exert potent immunosuppressive capacities in mice developing pathogenic autoimmune processes, including EAU, but its toxicity makes it unusable for humans. A recently identified endogenous AHR ligand, ITE, is also immunosuppressive, but is nontoxic and could therefore be useful for therapy in humans. Here, we tested ITE for its capacity to inhibit EAU and related immune responses. EAU was induced in B10.A mice by immunization with interphotoreceptor retinoid-binding protein (IRBP; 40 μg) in CFA. Treatment with ITE was by daily intraperitoneal injection of 0.2 mg. Disease severity was assessed by both fundoscopy and histological examination. Draining lymph node cells were tested for proliferation by thymidine uptake and for cytokine production and release by ELISA. In addition, the intracellular expression of cytokines and Foxp3 was determined by flow cytometry. Serum antibodies were measured by ELISA. Treatment with ITE efficiently inhibited the development of EAU in mice, as well as the cellular immune responses against IRBP and PPD. ITE treatment inhibited the expansion of both Th1 and Th17 subpopulations, as well as their release of the signature cytokines, IFN-gamma and IL-17. The treatment moderately increased, however, the proportion of Foxp3 expressing T-regulatory cells. Antibody production was not affected by the treatment. ITE, an endogenous AHR ligand, efficiently inhibits EAU development and related cellular immune responses. Being nontoxic, ITE may be considered for treatment of pathogenic immunity in humans.

A monitoring campaign of polychlorinated dibenzo-p-dioxins and dibenzofurans, polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyl was carried out in an Italian iron ore sintering plant by sampling the combustion gases at the electrostatic precipitator (ESP) outlet, at the Wetfine scrubber (WS) outlet, and by collecting the ESP dust. Few data are available on these micropollutants produced in iron ore sintering plants, particularly from Italian plants. This study investigates the PAH emission profiles and the removal efficiency of ESPs and WS. PAHs were determined at the stack, ESP outlet flue gases, and in ESP dust to characterize the emission profiles and the performance of the ESP and the WS for reducing PAH emission. The 11 PAHs monitored are listed in the Italian legislative decree 152/2006. The mean total PAH sum concentration in the stack flue gases is 3.96 {mu}g/N m{sup 3}, in ESP outlet flue gases is 9.73 {mu}g/N m{sup 3}, and in ESP dust is 0.53 {mu}g/g. Regarding the emission profiles, the most abundant compound is benzo(b)fluoranthene, which has a relative low BaP toxic equivalency factors (TEF) value, followed by dibenzo(a,l)pyrene, which has a very high BaP(TEF) value. The emission profiles in ESP dust and in the flue gases after the ESP show some changes, whereas the fingerprint in ESP and stack flue gases is very similar. The removal efficiency of the ESP and of WS on the total PAH concentration is 5.2 and 59.5%, respectively. 2 figs., 5 tabs.

This paper discusses the reforming of liquid hydrocarbons to produce hydrogen for fuel cell applications, focusing on gasoline and diesel due to their high hydrogen density and well-established infrastructures. Gasoline and diesel are composed of numerous hydrocarbon species including paraffins, olefins, cycloparaffins, and aromatics. We have investigated the reforming characteristics of several representative liquid hydrocarbons. In the case of paraffin reforming, H 2 yield and reforming efficiency were close to thermodynamic equilibrium status (TES), although heavier hydrocarbons required slightly higher temperatures than lighter hydrocarbons. However, the conversionefficiency was much lower for aromatics than paraffins with similar carbon number. We have also investigated the reforming performance of simulated commercial diesel and gasoline using simple synthetic diesel and gasoline compositions. Reforming performances of our formulations were in good agreement with those of commercial fuels. In addition, the reforming of gas to liquid (GTL) resulted in high H 2 yield and reforming efficiency showing promise for possible fuel cell applications.

Full Text Available Recently, much attention has been paid to the development of technologies that facilitate the conversion of biomass into platform chemicals such as 5-hydroxymethylfurfural (5-HMF. In this paper, a tin-containing silica molecular sieve (Sn-MCM-41 was found to act as a bifunctional heterogeneous catalyst for the efficientconversion of glucose into 5-HMF in ionic liquid. In the presence of [EMIM]Br, the yield of 5-HMF converted from glucose reached 70% at 110 °C after 4 h. During the reaction, the active center of the catalyst first catalyzed the isomerization of glucose into fructose and then the dehydration of fructose into 5-HMF. After the reaction, the heterogeneous catalyst Sn-MCM-41 could be easily recovered and reused without a significant loss in activity. The catalyst Sn-MCM-41 was also able to catalyze the conversion of fructose into 5-HMF at an 80% yield. Moreover, the low toxicity of the Sn-based catalyst makes the method a greener approach for the conversion of saccharides into 5-HMF.

Anatase TiO{sub 2} nanohexagon arrays were grown by using an anodization process of Ti foil in fluoride containing electrolytes. Photoanode based on the as-grown anatase TiO{sub 2} nanohexagon arrays for DSSCs showed a power photoconversion efficiency of 4.01% and incident photon-to-current conversionefficiency of 68%, which are significantly higher than those of the device based on anatase TiO{sub 2} nanotube arrays. This improvement in power conversionefficiency should be attributed to the fact that the nanotubes with hexagonal structure have higher surface area to allow the uploading of more dye molecules for light harvesting. Also, the spacing introduced inside the hexagon might allow the dye molecules to cover the interior of the walls. In addition, it is believed that the photoconversion efficiency can be further increased by optimizing the hexagonal structure through the electrochemical conditions. - Graphical abstract: Nanotubes with hexagonal structure have higher surface area to allow the uploading of more dye molecules for light harvesting in dye-sensitized solar cells. - Highlights: • A unique TiO{sub 2} nanohexagon arrays were grown by an anodization process. • Higher surface area for dye uploading provided by the hexagon structure. • TiO{sub 2} nanohexagon based photoanode has PCE of 4.01% and IPCE of 68%.

It would seem that the economic viability is yet to be established for a great number of sonochemical processes, owning to their perfectible ultrasonic equipments. Industrial scale sonoreactors may become more important as a result of mastering the parameters with influence on their energy balance. This work related the solvent type to the energy efficiency as the first step of a complex study aiming to assess the energy balance of sonochemical reactors at 500 kHz. Quantitative measurements of ultrasonic power for water and 10 pure organic solvents were performed by calorimetry for a cylindrically shaped sonochemical reactor with a bottom mounted vibrating plate. It was found that the ultrasonic power is strongly related to the solvent, the energy conversion for organic liquids is half from that of water and there is a drop in energy efficiency for filling levels up to 250 mm organic solvents. Surface tension, viscosity and vapor pressure influence the energy conversion for organic solvents, but it is difficult explain these findings based on physical properties of solvents alone. The apparent intensity of the atomization process shows a good agreement with the experimentally determined values for energy conversion for water and the solvent group studied here. This study revealed that to attain the same ultrasonic power level, more electrical energy is need for organic solvents as compared to water. The energy balance equation has been defined based on these findings by considering an energy term for atomization.

Context: Fast surface conversion between ortho- and para-H2 has been observed in laboratory studies, and this mechanism has been proposed to play a role in the control of the ortho-para ratio in the interstellar medium. Observations of rotational lines of H2 in Photo-Dissociation Regions (PDRs) have indeed found significantly lower ortho-para ratios than expected at equilibrium. The mechanisms controlling the balance of the ortho-para ratio in the interstellar medium thus remain incompletely understood, while this ratio can affect the thermodynamical properties of the gas (equation of state, cooling function). Aims: We aim to build an accurate model of ortho-para conversion on dust surfaces based on the most recent experimental and theoretical results, and to validate it by comparison to observations of H2 rotational lines in PDRs. Methods: We propose a statistical model of ortho-para conversion on dust grains with fluctuating dust temperatures, based on a master equation approach. This computation is then co...

A novel system concept is presented for the thermochemical conversion of very wet biomasses such as sewage sludge and manure. The system integrates steam drying, solid oxide electrolysis cells (SOEC) and gasification for the production of synthetic natural gas (SNG). The system is analyzed....... The analysis shows that the total efficiency of the novel system is 69–70% depending on the biomass ash content, while the biomass to SNG energy ratio is 165%, which is near the theoretical maximum because electrolytic hydrogen is supplied to the synthesis gas. It is proposed to combine the novel system...... with an anaerobic digester for conversion of biomasses with high nitrogen content, such as sewage sludge. The organic nitrogen in the sewage sludge will be mineralized in the digester instead of ending up as N2 in the SNG product....

A facilitated electrochemical reaction at the surface of electrodes is crucial for highly efficient energy conversion and storage. Herein, various nanoparticles (NPs) including Au, Pt, Pd, Ru, and RuO(2), were synthesized in situ and directly deposited on the ionic liquid (IL)-functionalized reduced graphene oxides (RGOs) in a controlled manner. The size, amount, and crystalline structures of discrete NPs were readily controlled, giving rise to enhanced methanol oxidation and pseudocapacitance. The well-defined nanostructure of decorated NPs and the favorable interaction between ILs and RGOs (or NPs) facilitated the electrochemical reaction, where NPs acted as electrocatalysts for energy conversion and played the role of redox-active electrodes for energy storage.

Recent work proposed up-conversion of sunlight through low-band-gap solar cells in combination with a large-band-gap light-emitting diode (LED), with one possibility being the use of a GaAs/Ge tandem photovoltaic device to drive a GaInP LED. One-sun limiting efficiencies for a GaInP bifacial solar cell with such an up-converter attached to its rear are reported for varying band-gap of GaInP junctions, both when there are radiative couplings between cells in the rear up-converter and when there are not. With a maximum theoretical efficiency of 44%, it is shown that the top cell's band-gap is a trade-off and radiative coupling in the rear up-converter reduces the efficiency, where physical reasons are given as is insight into the practice.

Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1200K. Both selective emitter and filter system TPV systems are feasible. However, requirements on the filter system are severe in order to attain high efficiency. A thin-film of a rare-earth oxide is one method for producing an efficient, rugged selective emitter. An efficiency of 0.14 and power density of 9.2 W/KG at 1200K is calculated for a hypothetical thin-film neodymia (Nd2O3) selective emitter TPV system that uses radioisotope decay as the thermal energy source.

Photosynthesis is nature's route to convert intermittent solar irradiation into storable energy, while its use for an industrial energy supply is impaired by low efficiency. Artificial photosynthesis provides a promising alternative for efficient robust carbon-neutral renewable energy generation. The approach of direct hydrogen generation by photoelectrochemical water splitting utilizes customized tandem absorber structures to mimic the Z-scheme of natural photosynthesis. Here a combined chemical surface transformation of a tandem structure and catalyst deposition at ambient temperature yields photocurrents approaching the theoretical limit of the absorber and results in a solar-to-hydrogen efficiency of 14%. The potentiostatically assisted photoelectrode efficiency is 17%. Present benchmarks for integrated systems are clearly exceeded. Details of the in situ interface transformation, the electronic improvement and chemical passivation are presented. The surface functionalization procedure is widely applicable and can be precisely controlled, allowing further developments of high-efficiency robust hydrogen generators.

Full Text Available Background and Objectives: Remaining of crude oil in storage tanks usually results in accumulating oily sludge at the bottom of the tank, which should be treated and disposed of in a suitable manner. The efficiency of in-vessel composting process in removing total petroleum hydrocarbons (TPH from bottom sludge of crude oil storage tanks was investigated in the present study. Material and methods: The sludge was mixed with immature compost at the ratios of 1:0 (as control, 1:2, 1:4, 1:6, 1:8, and 1:10 (as dry basis with the initial C:N:P and moisture content of 100:5:1 and 55% respectively for a period of 10 weeks. The moisture adjustment and mixing process were done 3 times a day during the composting period. Sampling and analysis of TPH and pH were done every week and every two days, respectively. Results: TPH removal in the 1:2, 1:4, 1:6, 1:8, and 1:10 composting reactors was 66.59, 73.19, 74.81, 80.20, and 79.91%, respectively. Thus, initial adjustment of sludge to immature compost ratios plays a great role in reduction of TPH. The results of the control reactors indicated that the main mechanism of TPH removal in the composting reactors was biological process. Conclusions: In-vessel composting by addition of immature compost as amendment is a viable choice for bioremediation of the bottom sludge of crude oil storage tanks.

Full Text Available Dye-sensitized solar cells (DSSCs based on a TiO2 photoanode have been considered as an alternative source in the field of renewable energy resources. In DSSCs, photoanode plays a key role to achieve excellent photo-to-electric conversionefficiency. The surface morphology, surface area, TiO2 crystal phase, and the dispersion of TiO2 nanoparticles are the most important factors influencing the properties of a photoanode. The smooth TiO2 surface morphology of the photoanode indicates closely packed arrangement of TiO2 particles which enhance the light harvesting efficiency of the cell. In this paper, a smooth TiO2 photoanode has been successfully prepared using a well-dispersed anatase TiO2 nanosol via a simple hydrothermal process. The above TiO2 photoanode was then compared with the photoanode made from commercial TiO2 nanoparticle pastes. The morphological and structural analyses of both the aforementioned photoanodes were comprehensively characterized by scanning electron microscopy and X-ray diffraction analysis. The DSSC fabricated by using a-TiO2 nanosol-based photoelectrode exhibited an overall light conversionefficiency of 7.20% and a short-circuit current density of 13.34 mA cm−2, which was significantly higher than those of the DSSCs with the TiO2 nanoparticles-based electrodes.

In spite of the impressive development achieved by organic photovoltaics throughout the last decades, especially in terms of reported power conversionefficiencies, there are still important technological and fundamental obstacles to circumvent before they can be implemented into reliable and long-lasting applications. Regarding device processing, the synthesis of highly soluble polymeric semiconductors first, and then fullerene derivatives, was initially considered as an important breakthrough that would definitely change the fabrication of photovoltaics once and for all. The potential and the expectation raised by this technology is such that it is very difficult to keep track of the most significant progresses being now published in different and even monographic journals. In this paper, we review the development of polymeric solar cells from its origin to the most efficient devices published to date. We separate these achievements into three different categories traditionally followed by the scientific community to push devices over 10% power conversionefficiency: active materials, strategies-fabrication/processing procedures-that can mainly modify the active film morphology, and all the different cell layout/architectures that have been used in order to extract as high a photocurrent as possible from the Sun. The synthesis of new donors, the use of additives and postprocessing techniques, buffer interlayers, inverted and tandem designs are some of the most important aspects that are reviewed in detail in this paper. All have equally contributed to develop this technology and bring it at the doors of commercialization.

Nano-scaled metallic or dielectric structures may provide various ways to trap light into thin-film solar cells for improving the conversionefficiency. In most schemes, the textured active layers are involved into light trapping structures that can provide perfect optical benefits but also bring undesirable degradation of electrical performance. Here we propose a novel approach to design high-performance thin-film solar cells. In our strategy, a flat active layer is adopted for avoiding electrical degradation, and an optimization algorithm is applied to seek for an optimized light trapping structure for the best optical benefit. As an example, we show that the efficiency of a flat a-Si:H thin-film solar cell can be promoted close to the certified highest value. It is also pointed out that, by choosing appropriate dielectric materials with high refractive index (>3) and high transmissivity in wavelength region of 350nm-800nm, the conversionefficiency of solar cells can be further enhanced.

Full Text Available A white light source using direct phosphor-conversion excited by a blue laser diode is presented. In this preliminary study we have investigated the influence of phosphor’s thickness and operating current of the laser diode over the (x, y chromaticity coordinates, Correlated Color Temperature (CCT and Color Rendering Index (CRI. The best values found were 4000 K and 94. A 40 lm/W luminous efficacy was achieved together with a CRI close to 90 for an operating current of 0.8 A. Those values, to the best of our knowledge, were not previously reported in the literature.

In this article, 20 kW ocean thermal energy conversion with a vapor–vapor ejector is newly proposed. As a vapor–vapor ejector is installed in the system, the pressure difference between the turbine inlet and outlet increases. Therefore, the amount of the working fluid required for the total turbine work of 20 kW is less than when no vapor–vapor ejector is installed. Therefore, installing a vapor–vapor ejector in the system decreases the evaporation capacity and the pump work. The performance ...

This technology pathway case investigates the upgrading of woody biomass derived synthesis gas (syngas) to hydrocarbon biofuels. While this specific discussion focuses on the conversion of syngas via a methanol intermediate to hydrocarbon blendstocks, there are a number of alternative conversion routes for production of hydrocarbons through a wide array of intermediates from syngas. Future work will also consider the variations to this pathway to determine the most economically viable and lowest risk conversion route. Technical barriers and key research needs have been identified that should be pursued for the syngas-to-hydrocarbon pathway to be competitive with petroleum-derived gasoline-, diesel- and jet-range hydrocarbon blendstocks.

The efficiency of the solar collector consisting of a selective absorber and a selective transparent filter is derived for comparing and evaluating the collectors. The efficiency of Drude mirror type selective transparent filters is calculated in cases of a blackbody absorber and the Al(2)O(3)-Mo-Al(2)O(3)-Mo highly selective absorber. As Drude mirrors, Sn-doped In(2)O(3) films were formed on Pyrex glass plates by rf sputtering, and the dependence of the efficiencies on the operating conditions of the collector, including solar concentration and temperature of the absorber, is discussed.

Up-conversion single photon detector (UCSPD) has been widely used in many research fields including quantum key distribution (QKD), lidar, optical time domain reflectrometry (OTDR) and deep space communication. For the first time in laboratory, we have developed an integrated four-channel all-fiber UCSPD which can work in both free-running and gate modes. This compact module can satisfy different experimental demands with adjustable detection efficiency and dark count. We have characterized the key parameters of the UCSPD system.

Dye-sensitized solar cells (DSSCs) based on a TiO2 photoanode have been considered as an alternative source in the field of renewable energy resources. In DSSCs, photoanode plays a key role to achieve excellent photo-to-electric conversionefficiency. The surface morphology, surface area, TiO2 crystal phase, and the dispersion of TiO2 nanoparticles are the most important factors influencing the properties of a photoanode. The smooth TiO2 surface morphology of the photoanode indicates closely ...

Nano metal-enhanced power conversionefficiency (PCE) in CH3NH3PbI3 solar cells utilizing the forward scattering effect of metal nanoparticles has been researched in this paper by finite difference time domain method. Two structures are designed in the research to explore this feasibility, by adjusting the materials, sizes and surface coverages of metal nanoparticles, both of them exhibit the exciting results bringing the max PCE enhancements by 12.18% and 8.03% respectively. Especially, considering the huge handleability of the second structure, this method has large applications in further improving the performance for other perovskite solar cells.

In this paper, we present an active rectifier with high power conversionefficiency (PCE) implemented in a 0.5- mum 5 V standard CMOS technology with two modes of built-in back telemetry; short- and open-circuit. As a rectifier, it ensures a PCE > 80%, taking advantage of active synchronous rectification technique in the frequency range of 0.125-1 MHz. The built-in complementary back telemetry feature can be utilized in implantable microelectronic devices (IMD), wireless sensors, and radio frequency identification (RFID) applications to reduce the silicon area, increase the data rate, and improve the reading range and robustness in load shift keying (LSK).

An effective way to improve polymer solar cell efficiency is to use a tandem structure, as a broader part of the spectrum of solar radiation is used and the thermalization loss of photon energy is minimized...

The kinds and the distribution of the coal in China areinvestigated in this paper. The results indicated that the 80% coalin China is used by the method of the coal gasification. Thepossibility of utilization and development of the fuel cell powerplant in China is analyzed. A combined cycle generation system isdesigned. Its net electrical efficiency is about 55%(LHV), which ishigher than that of the fire power plant. So it isenvironmental-friendly and high-efficient generation mode.

A process for production and recovery of hydrocarbons from hydrocarbon-containing whole plants in a form suitable for use as chemical feedstocks or as hydrocarbon energy sources which process comprises: (A) pulverizing by grinding or chopping hydrocarbon-containing whole plants selected from the group consisting of euphorbiaceae, apocynaceae, asclepiadaceae, compositae, cactaceae and pinaceae families to a suitable particle size, (B) drying and preheating said particles in a reducing atmosphere under positive pressure (C) passing said particles through a thermal conversion zone containing a reducing atmosphere and with a residence time of 1 second to about 30 minutes at a temperature within the range of from about 200* C. To about 1000* C., (D) separately recovering the condensable vapors as liquids and the noncondensable gases in a condition suitable for use as chemical feedstocks or as hydrocarbon fuels.

Combustion efficiency and altitude operational limits were determined in a J33 single combustor for AN-F-58 fuel and three liquid hydrocarbon fuels having high volumetric energy content (decalin, tetralin, and monomethylnaphthalene) at simulated altitude and combustor inlet-air conditions. At the conditions investigated, the combustion efficiency for the four fuels generally decreased with an increase in volumetric energy content. The altitude operational limits for decalin and tetralin fuels were higher than for AN-F-58 fuel; monomethylnaphthalene fuel gave the lowest altitude operational limit.

This work demonstrates the first molecular-level conversion pathway of NO oxidation over a novel SrO-clusters@amorphous carbon nitride (SCO-ACN) photocatalyst, which is synthesized via copyrolysis of urea and SrCO3. The inclusion of SrCO3 is crucial in the formation of the amorphous carbon nitride (ACN) and SrO clusters by attacking the intralayer hydrogen bonds at the edge sites of graphitic carbon nitride (CN). The amorphous nature of ACN can promote the transportation, migration, and transformation of charge carriers on SCO-ACN. And the SrO clusters are identified as the newly formed active centers to facilitate the activation of NO via the formation of Sr-NO(δ(+)), which essentially promotes the conversion of NO to the final products. The combined effects of the amorphous structure and SrO clusters impart outstanding photocatalytic NO removal efficiency to the SCO-ACN under visible-light irradiation. To reveal the photocatalytic mechanism, the adsorption and photocatalytic oxidation of NO over CN and SCO-ACN are analyzed by in situ DRIFTS, and the intermediates and conversion pathways are elucidated and compared. This work presents a novel in situ DRIFTS-based strategy to explore the photocatalytic reaction pathway of NO oxidation, which is quite beneficial to understand the mechanism underlying the photocatalytic reaction and advance the development of photocatalytic technology for environmental remediation.

Full Text Available Generally, an activity is considered to be efficient if the production implies low costs or if the revenues from selling the products on the market outweigh the expenditures that were made to achieve them. Labor productivity as an efficiency indicator of a production process represents an expression of the relationship between effect (products, services and effort (work means, labor force, work items. Through the labor productivity conversion in rates of return (economic and commercial is determined an evolution and an influence on these rates, driving the company’s own efforts to innovate, produce and harness goods, works and services with maximum utility, efficiency and competitiveness services. The aim of this paper is to highlight the work efficiency, respectively the labor productivity detached from the factorial context in the trade and economic rates of return. The introduction presents some general aspects referring to labor productivity, then it will be presented and discussed the analytical methods used in the process of reflecting the labor productivity in the rates of return, the results analysis, and at the end of this paper it will be presented some conclusions based on the study case. The expected results consist in identifying the mechanisms by which labor efficiency is converted into the company’s economic and financial performance.

This paper describes a unique system that is used to mix and blend multiple batches of plutonium oxide powder of various consistencies into an equivalent number of identical and homogeneously mixed batches. This system is being designed and built to support the Advanced Recovery and Integrated Extraction System (ARIES) at the Los Alamos TA-55 Plutonium Facility. The ARIES program demonstrates dismantlement of nuclear pits, retrieval of the plutonium components, and conversion of the plutonium into an oxide for eventual use in mixed oxide (MOX) fuel for nuclear reactors. The purpose of this powder blending work is to assure that ARIES oxide is converted into an unclassified homogeneous mixture and that consistent feed material is available for MOX fuel assembly. This blending system is being assembled in a selected glovebox a TA-55 using an LANL designed split/combine apparatus, a commercial Turbula blending unit, and several additional supporting hardware components.

Full Text Available The output power of photovoltaic systems is directly related to the amount of solar energy collected by the system and it is therefore necessary to track the sun’s position with high accuracy. This study proposes multi-agent adaptive critic based nero fuzzy solar tracking system dedicated to PV panels. The proposed tracker ensures the optimal conversion of solar energy into electricity by properly adjusting the PV panels according to the position of the sun. To evaluate the usefulness of the proposed method, some computer simulations are performed and compared with fuzzy PD controller. Obtained results show the proposed control strategy is very robust, flexible and could be used to get the desired performance levels. The response time is also very fast. Simulation results that have been compared with fuzzy PD controller show that our method has the better control performance than fuzzy PD controller.

Nitrogen fixation is essential for the synthesis of many important chemicals (e.g., fertilizers, explosives) and basic building blocks for all forms of life (e.g., nucleotides for DNA and RNA, amino acids for proteins). However, direct nitrogen fixation is challenging as nitrogen (N2) does not easily react with other chemicals. By dry ball-milling graphite with N2, we have discovered a simple, but versatile, scalable and eco-friendly, approach to direct fixation of N2 at the edges of graphene nanoplatelets (GnPs). The mechanochemical cracking of graphitic C-C bonds generated active carbon species that react directly with N2 to form five- and six-membered aromatic rings at the broken edges, leading to solution-processable edge-nitrogenated graphene nanoplatelets (NGnPs) with superb catalytic performance in both dye-sensitized solar cells and fuel cells to replace conventional Pt-based catalysts for energy conversion.

Nitrogen fixation is essential for the synthesis of many important chemicals (e.g., fertilizers, explosives) and basic building blocks for all forms of life (e.g., nucleotides for DNA and RNA, amino acids for proteins). However, direct nitrogen fixation is challenging as nitrogen (N₂) does not easily react with other chemicals. By dry ball-milling graphite with N₂, we have discovered a simple, but versatile, scalable and eco-friendly, approach to direct fixation of N₂ at the edges of graphene nanoplatelets (GnPs). The mechanochemical cracking of graphitic C--C bonds generated active carbon species that react directly with N₂ to form five- and six-membered aromatic rings at the broken edges, leading to solution-processable edge-nitrogenated graphene nanoplatelets (NGnPs) with superb catalytic performance in both dye-sensitized solar cells and fuel cells to replace conventional Pt-based catalysts for energy conversion.

A monolithic compound semiconductor phototransducer optimized for narrow-band light sources was designed for and has achieved conversionefficiencies exceeding 50%. The III-V heterostructure was grown by MOCVD, based on the vertical stacking of a number of partially absorbing GaAs n/p junctions connected in series with tunnel junctions. The thicknesses of the p-type base layers of the diodes were engineered for optimal absorption and current matching for an optical input with wavelengths centered in the 830 nm to 850 nm range. The device architecture allows for improved open-circuit voltage in the individual base segments due to efficient carrier extraction while simultaneously maintaining a complete absorption of the input photons with no need for complicated fabrication processes or reflecting layers. Progress for device outputs achieving in excess of 12 V is reviewed in this study.

Dye-sensitized solar cells (DSSCs) were fabricated using open-ended freestanding TiO₂ nanotube arrays functionalized with Ag nanoparticles (NPs) in the channel to create a plasmonic effect, and then coated with large TiO₂ NPs to create a scattering effect in order to improve energy conversionefficiency. Compared to closed-ended freestanding TiO₂ nanotube array-based DSSCs without Ag or large TiO₂ NPs, the energy conversionefficiency of closed-ended DSSCs improved by 9.21% (actual efficiency, from 5.86% to 6.40%) with Ag NPs, 6.48% (actual efficiency, from 5.86% to 6.24%) with TiO₂ NPs, and 14.50% (actual efficiency, from 5.86% to 6.71%) with both Ag NPs and TiO₂ NPs. By introducing Ag NPs and/or large TiO₂ NPs to open-ended freestanding TiO₂ nanotube array-based DSSCs, the energy conversionefficiency was improved by 9.15% (actual efficiency, from 6.12% to 6.68%) with Ag NPs and 8.17% (actual efficiency, from 6.12% to 6.62%) with TiO₂ NPs, and by 15.20% (actual efficiency, from 6.12% to 7.05%) with both Ag NPs and TiO₂ NPs. Moreover, compared to closed-ended freestanding TiO₂ nanotube arrays, the energy conversionefficiency of open-ended freestanding TiO₂ nanotube arrays increased from 6.71% to 7.05%. We demonstrate that each component-Ag NPs, TiO₂ NPs, and open-ended freestanding TiO₂ nanotube arrays-enhanced the energy conversionefficiency, and the use of a combination of all components in DSSCs resulted in the highest energy conversionefficiency.

To provide a front transparent electrode for use in highly efficient hydrogenated amorphous silicon (a-Si:H) thin-film solar cells, porous flat layer and micro-patterns of zinc oxide (ZnO) nanoparticle (NP) layers were prepared through ultraviolet nanoimprint lithography (UV-NIL) and deposited on Al-doped ZnO (AZO) layers. Through this, it was found that a porous micro-pattern of ZnO NPs dispersed in resin can optimize the light-trapping pattern, with the efficiency of solar cells based on patterned or flat mesoporous ZnO layers increased by 27% and 12%, respectively.

Resonant second harmonic generation between 1550 nm and 775 nm with outside efficiency $> 4.4\\times10^{-4}\\, \\text{mW}^{-1}$ is demonstrated in a gallium phosphide microdisk cavity supporting high-$Q$ modes at visible ($Q \\sim 10^4$) and infrared ($Q \\sim 10^5$) wavelengths. The double resonance condition was satisfied through intracavity photothermal temperature tuning using $\\sim 360\\,\\mu$W of 1550 nm light input to a fiber taper and resonantly coupled to the microdisk. Above this pump power efficiency was observed to decrease. The observed behavior is consistent with a simple model for thermal tuning of the double resonance condition.

Despite advances in photothermal therapy of gold nanoshells, reliable evaluations of their size dependence on the relative biological effects are needed. We report the size effects of PEGylated gold nanoshells on silica nanorattles (pGSNs) on their cellular uptake, in vivo fate and light-heat conversionefficiency in this study. The results indicate that smaller pGSNs have enhanced cellular uptake by the MCF-7 cells. For in vivo biodistribution study, pGSNs of different particle sizes (84-315 nm) distribute mainly in the liver and spleen in MCF-7 tumor-bearing BALB/c nude mice. Smaller pGSNs have a longer blood-circulation lifetime and higher light-heat conversionefficiency both in vitro and in vivo compared with larger ones. All three sizes of pGSNs can be excreted from the mice body at a slow rate and do not cause tissue toxicity after intravenous injection at a dosage of 20 mg kg(-1) for three times. The data support the feasibility of optimizing the therapeutic process for photothermal cell killing by plasmonic gold nanoshells.

Full Text Available Photoelectrochemical (PEC water splitting for hydrogen generation has been considered as a promising route to convert and store solar energy into chemical fuels. In terms of its large-scale application, seeking semiconductor photoelectrodes with high efficiency and good stability should be essential. Although an enormous number of materials have been explored for solar water splitting in the last several decades, challenges still remain for the practical application. P-type copper-based chalcogenides, such as Cu(In, GaSe2 and Cu2ZnSnS4, have shown impressive performance in photovoltaics due to narrow bandgaps, high absorption coefficients, and good carrier transport properties. The obtained high efficiencies in photovoltaics have promoted the utilization of these materials into the field of PEC water splitting. A comprehensive review on copper-based chalcogenides for solar-to-hydrogen conversion would help advance the research in this expanding area. This review will cover the physicochemical properties of copper-based chalco-genides, developments of various photocathodes, strategies to enhance the PEC activity and stability, introductions of tandem PEC cells, and finally, prospects on their potential for the practical solar-to-hydrogen conversion. We believe this review article can provide some insights of fundamentals and applications of copper-based chalco-genide thin films for PEC water splitting.

Photoelectrochemical (PEC) water splitting for hydrogen generation has been considered as a promising route to convert and store solar energy into chemical fuels. In terms of its large-scale application, seeking semiconductor photoelectrodes with high efficiency and good stability should be essential. Although an enormous number of materials have been explored for solar water splitting in the last several decades, challenges still remain for the practical application. P-type copper-based chalcogenides, such as Cu(In, Ga)Se2 and Cu2ZnSnS4, have shown impressive performance in photovoltaics due to narrow bandgaps, high absorption coefficients, and good carrier transport properties. The obtained high efficiencies in photovoltaics have promoted the utilization of these materials into the field of PEC water splitting. A comprehensive review on copper-based chalcogenides for solar-to-hydrogen conversion would help advance the research in this expanding area. This review will cover the physicochemical properties of copper-based chalco-genides, developments of various photocathodes, strategies to enhance the PEC activity and stability, introductions of tandem PEC cells, and finally, prospects on their potential for the practical solar-to-hydrogen conversion. We believe this review article can provide some insights of fundamentals and applications of copper-based chalco-genide thin films for PEC water splitting.

Full Text Available The objective of the study is to present the modeling and multi-objective optimization of NOx conversionefficiency and NH3 slip in the Selective Catalytic Reduction (SCR catalytic converter for a diesel engine. A novel ensemble method based on a support vector machine (SVM and genetic algorithm (GA is proposed to establish the models for the prediction of upstream and downstream NOx emissions and NH3 slip. The data for modeling were collected from a steady-state diesel engine bench calibration test. After obtaining the two conflicting objective functions concerned in this study, the non-dominated sorting genetic algorithm (NSGA-II was implemented to solve the multi-objective optimization problem of maximizing NOx conversionefficiency while minimizing NH3 slip under certain operating points. The optimized SVM models showed great accuracy for the estimation of actual outputs with the Root Mean Squared Error (RMSE of upstream and downstream NOx emissions and NH3 slip being 44.01 × 10−6, 21.87 × 10−6 and 2.22 × 10−6, respectively. The multi-objective optimization and subsequent decisions for optimal performance have also been presented.

We present a detailed theoretical investigation of cladding-pumped Raman fiber amplification in an unexplored parameter space of high conversionefficiency (> 60%) and high brightness enhancement (> 1000). Fibers with large clad-to-core diameter ratios can provide a promising means for Raman-based brightness enhancement of diode pump sources. Unfortunately, the diameter ratio cannot be extended indefinitely since the intensity generated in the core can greatly exceed that in the cladding long before the pump is fully depleted. If left uncontrolled, this leads to the generation of parasitic second-order Stokes wavelengths in the core, limiting the conversionefficiency and as we will show, clamping the achievable brightness enhancement. Using a coupled-wave formalism, we present the upper limit on brightness enhancement as a function of diameter ratio for conventionally guided fibers. We further present strategies for overcoming this limit based upon depressed well core designs. We consider two configurations: 1) pulsed cladding-pumped Raman fiber amplifier (CPRFA) and 2) cw cladding-pumped Raman fiber laser (CPRFL).

TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites were prepared by hydrothermal method for dye sensitized solar cell (DSSC) application. The structural and optical properties were investigated by X -ray diffraction (XRD) and UV-Visible spectroscopy respectively. XRD results revealed the formation of material in nano size. The average crystallite size is 22.32 nm, 17.41 nm and 6.31 nm for TiO2, TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites respectively. The optical bandgap varies from 2.04 eV to 3.75 eV. Dye sensitized solar cells were fabricated using the prepared material. Pomegranate juice was used as a sensitizer and graphite coated conducting glass plate was used as counter electrode. The I - V characteristics were recorded to measure photo response of DSSC. Photovoltaic parameter like open circuit voltage, power conversionefficiency, and fill factor were evaluated for fabricated solar cell. The power conversionefficiency of DSSC fabricated with TiO2, TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites were found 0.71%, 1.97% and 4.58% respectively.

A review of conversionefficiency and its influencers in marine fishes is presented in this paper. The conversionefficiency is the efficiency of food utilization for growth, usually expressed as energy conversionefficiency, i. e, growth efficiency, when measured in energy, or food conversionefficiency when measured in biomass. So, estimation of conversionefficiency is basically a work on determinations of food consumption and weight growth of fish. Influence factor of conversionefficiency are mostly those influencing food consumption and weight growth, containing abiotic, biotic, and physiological factors, and limitations of controlled conditions in experiments, in many cases, which leads to results not reflecting the natural states. The abiotic influencers include water temperature, salinity, pH, dissolved oxygen, ammonia nitrogen, current surrounding, and photoperiod, of which water temperature and photoperiod are the most important. In experiments without food limitation, the growth rate of fish increases generally with rising of water temperature, and reaches a maximum at an optimum temperature. But that the optimum temperature for growth goes down at low ration levels indicates that the temperature influence on growth depends upon food availability for fishes. The photoperiod can speed up or keep down the fish growth with its alternation during a year. The biotic influencers contain food availability, competition, and predation. The food availability is considered as a key factor, as important as water temperature, manipulating food consumption and growth of fish, It is density dependent and is diversified temporally and spatially due to climate change, physical and chemical oceanography processes in the ecosystem. The availability of food that contains high calorie is a primary reason why food type shifts evidently the food conversionefficiency in a species of fish. Comparatively, the energy conversionefficiency is much more steady with the change of

implementing tertiary regulation. Moreover, system dynamic is affected when shifting VRs. Therefore, the stability is considered in optimization by constraining the eigenvalues arising from dynamic state space model of the system. Genetic algorithm is used in searching for global efficiency optimum while...

This study investigated the effect of maternal energy efficiency on broiler chicken growth and energy efficiency from 7 to 40 d of age. Residual feed intake (RFI) and residual maintenance ME requirement (RME) were used to measure energetic efficiency. Residual feed intake was defined as the difference between observed and predicted ME intake, and RME(m) as the difference between observed and predicted maintenance ME requirements. A total of 144 Ross-708 broiler breeder pullets were placed in individual laying cages at 16 wk of age. Hens with the greatest RFI (n = 32) and lowest RFI (n = 32) values from 20 to 56 wk of age were selected (maternal RFI; RFI(mat)). Selected hens were retrospectively assigned to a high- or low-RME(m) category (maternal RME(m); RME(mmat)). At 59 wk, eggs were collected for 8 d and pedigree hatched. A total of 338 broilers grouped by dam and sex were raised in 128 cages where feed intake, BW, and temperature were recorded from 7 to 40 d to calculate broiler feed conversion ratios, RFI, and RME(m). The design was a 2 × 2 × 2 factorial with 2 levels of RFI(mat), 2 levels of RME(mmat), and 2 sexes. Neither the RFI(mat) nor RME(mmat) category affected broiler offpring BW or total conversion ratio. The high-RFI(mat) × low-RME(mmat) broilers had decreased growth to 40 d. Low-RFI(mat) × low-RME(mmat) broilers had a lower RME(m) (-5.93 kcal of ME/kg(0.60) per day) and RFI (-0.86 kcal of ME/d) than high-RFI(mat) × low-RME(mmat) broilers (RME(m) = 1.70 kcal of ME/kg(0.60) per day; RFI = 0.38 kcal of ME/d). Overall, hens with low maintenance requirements (low RME(m)) produced more efficient broilers when other efficiency related traits, represented in a lower RFI, were present. Exclusion of high-RFI × low-RME(m) hens from selection programs may improve energy efficiency at the broiler level. The RME(m) methodology is a viable alternative to evaluate energy efficiency in broilers because it avoids confounding environmental effects and allows

Three-dimensional (3-D) structures have triggered tremendous interest for thin-film solar cells since they can dramatically reduce the material usage and incident light reflection. However, the high aspect ratio feature of some 3-D structures leads to deterioration of internal electric field and carrier collection capability, which reduces device power conversionefficiency (PCE). Here, we report high performance flexible thin-film amorphous silicon solar cells with a unique and effective light trapping scheme. In this device structure, a polymer nanopillar membrane is attached on top of a device, which benefits broadband and omnidirectional performances, and a 3-D nanostructure with shallow dent arrays underneath serves as a back reflector on flexible titanium (Ti) foil resulting in an increased optical path length by exciting hybrid optical modes. The efficient light management results in 42.7% and 41.7% remarkable improvements of short-circuit current density and overall efficiency, respectively. Meanwhile, an excellent flexibility has been achieved as PCE remains 97.6% of the initial efficiency even after 10 000 bending cycles. This unique device structure can also be duplicated for other flexible photovoltaic devices based on different active materials such as CdTe, Cu(In,Ga)Se2 (CIGS), organohalide lead perovskites, and so forth.

Full Text Available BACKGROUND: Phenyllactic acid (PLA, a novel antimicrobial compound with broad and effective antimicrobial activity against both bacteria and fungi, can be produced by many microorganisms, especially lactic acid bacteria. However, the concentration and productivity of PLA have been low in previous studies. The enzymes responsible for conversion of phenylpyruvic acid (PPA into PLA are equivocal. METHODOLOGY/PRINCIPAL FINDINGS: A novel thermophilic strain, Bacillus coagulans SDM, was isolated for production of PLA. When the solubility and dissolution rate of PPA were enhanced at a high temperature, whole cells of B. coagulans SDM could effectively convert PPA into PLA at a high concentration (37.3 g l(-1 and high productivity (2.3 g l(-1 h(-1 under optimal conditions. Enzyme activity staining and kinetic studies identified NAD-dependent lactate dehydrogenases as the key enzymes that reduced PPA to PLA. CONCLUSIONS/SIGNIFICANCE: Taking advantage of the thermophilic character of B. coagulans SDM, a high yield and productivity of PLA were obtained. The enzymes involved in PLA production were identified and characterized, which makes possible the rational design and construction of microorganisms suitable for PLA production with metabolic engineering.

Nitrous acid (HONO) is an important source of hydroxyl radical (OH) which determines the fate of many chemically active and climate relevant trace gases. However, the sources and the formation mechanisms of HONO remain poorly understood. In this study, the effect of SO2 on the heterogeneous reactions of NO2 on MgO as a mineral dust surrogate was investigated. The reactivity of MgO to NO2 is weak while coexisting SO2 can increase the uptake coefficients of NO2 on MgO by 2-3 orders of magnitude. The uptake coefficients of NO2 on SO2-aged MgO are independent of NO2 concentrations in the range of 20-160 ppbv and relative humidity (0-70%RH). The reaction mechanism was demonstrated to be a redox reaction between NO2 and surface sulfite. In the presence of SO2, NO2 was reduced to nitrite under dry condition which could be further converted to gas-phase HONO in humid conditions. These results suggest that the reductive effect of SO2 on the heterogeneous conversion of NO2 to HONO may have a significant contribution to the unknown sources of HONO observed in polluted areas, for example in China.

The presence of phospholipid has been a challenge in liquid enzymatic biodiesel production. Among six lipases that were screened, lipase AY had the highest hydrolysis activity and a competitive transesterification activity. However, it yielded only 21.1% FAME from oil containing phospholipids. By replacing portions of these lipases with a more robust bioFAME lipase, CalT, the combination of lipase AY-CalT gave the highest FAME yield with the least amounts of free fatty acids and partial glycerides. A higher methanol addition rate reduced FAME yields for lipase DF-CalT and A10D-CalT combinations while that of lipase AY-CalT combination improved. Optimizing the methanol addition rate for lipase AY-CalT resulted in a FAME yield of 88.1% at 2h and more than 95% at 6h. This effective use of lipases could be applied for the rapid and economic conversion of unrefined oils to biodiesel.

We revisit Morrison and Osterle (1965) who derived a phenomenological expression for the ‘figure-of-merit’ {β\\text{EK}} of the electrokinetic energy conversion (EKEC) of a pressure difference into electric energy (and vice versa) using charged nanotubes, nanopores or ion-exchange membranes. We show the equivalence with Morrison and Osterle of a novel expression of {β\\text{EK}} derived by Bentien et al (2013). We analyze two physical models for ionic and solvent flow which directly relate {β\\text{EK}} to nanopore characteristics such as pore size and wall charge density. For the uniform potential model, we derive an analytical expression as a function of pore size, viscosity, ion diffusion coefficients and membrane charge density, and compare results with the full space-charge model by Osterle and co-workers as a function of pore size and ion diffusion coefficient. We present a novel expression for {β\\text{EK}} for salt solutions with ions with unequal diffusion coefficients (mobilities) and show that to increase {β\\text{EK}} the counterion mobility must be low and the coion mobility high.

The fermentation ability of thermotolerant Kluyveromyces marxianus BUNL-21 isolated in Laos was investigated. Comparison with thermotolerant K. marxianus DMKU3-1042 as one of the most thermotolerant yeasts isolated previously revealed that the strain possesses stronger ability for conversion of xylose to ethanol, resistance to 2-deoxyglucose in the case of pentose, and tolerance to various stresses including high temperature and hydrogen peroxide. K. marxianus BUNL-21 was found to have ethanol fermentation activity from xylose that is slightly lower and much higher than that of Scheffersomyces stipitis (Pichia stipitis) at 30 °C and at higher temperatures, respectively. The lower ethanol production seems to be due to large accumulation of acetic acid. The possible mechanism of acetic acid accumulation is discussed. In addition, it was found that both K. marxianus strains produced ethanol in the presence of 10 mM hydroxymethylfurfural or furfural, at a level almost equivalent to that in their absence. Therefore, K. marxianus BUNL-21 is a highly competent yeast for high-temperature ethanol fermentation with lignocellulosic biomass.

A novel enzyme membrane reactor with sandwich structure has been developed by confining glucosidase between two sheets of ultrafiltration membranes to effectively convert maltose to isomaltooligosaccharides (IMOs). The hydrophilic ultrafiltration membranes, which were prepared by phase inversion method using PES as bulk polymer and Pluronic F127 as both surface modification and pore formation agent, exhibited the desirable enzyme adsorption-resistant property. The scanning electron microscopy (SEM) photographs showed that two sheets of PES/Pluronic F127 membranes were packed tightly and glucosidase was kept in a free state within a nanoscale space. When the weight ratio of Pluronic F127 to PES was 30%, glucosidase could be completely rejected by the membranes. Due to the sandwich structuring of the membrane reactor and the high hydrophilicity of the PES/Pluronic F127 membrane surface, maltose conversion and yield reached 100% and 58% under the optimum experimental conditions (pH 6.0, 50 degrees C), respectively. 2010 Elsevier Ltd. All rights reserved.

Full Text Available To achieve large-scale low-cost ex vitro acclimatization of Siberian ginseng plants, heart- and torpedo-shaped secondary somatic embryos (SEs induced from germinated SEs on agar medium were collected and then inoculated to 10-l bubble column bioreactor, respectively. For plantlet conversion, inoculation of torpedo-shaped secondary SEs was more effective than heart-shaped SEs. TS2 (culture of torpedo-shaped SEs in a bioreactor with a 2-week subculture interval plantlets had a higher root number and leaf number and larger leaf area than did HS3 (culture of heart-shaped SEs in a bioreactor with a 3-week subculture interval and HS2 (culture of heart-shaped SEs in a bioreactor with a 2-week subculture interval plantlets. Of these converted plants, TS2 plantlets had higher survival rate (83.7% and growth characteristics after transplantation in a simple shed covered with a 50% sunshade net only for 6 months. TS2 plantlets also showed significantly lower H2O2 content and significantly increased superoxide dismutase (SOD, glutathione peroxidase (GPX, and glutathione transferase (GST expression levels as compared to HS2 plants when exposure to ex vitro conditions.

X-ray sources are created at the Nova and Omega laser by irradiating a confined volume of Ar, Xe, or Kr gas. The gas is heated by forty 0.35 {micro}m wavelength, 1-ns square laser beams to produce He-like ions that radiate K-shell emission over mm-sized dimensions. The targets are designed to be ''underdense'', meaning that the initial gas density is lower than the critical density of the laser, n{sub c} {approx} 10{sup 21} cm{sup -3}. The laser energy is primarily absorbed by inverse bremsstrahlung and a supersonic heat wave efficiently ionizes the gas. Results from time-resolved and time-integrated diagnostics over a range of experimental parameters are compared. This work represents an important, new method for development of efficient, large-area, tailored multi-keV x-ray sources.

Full Text Available By integrating the restriction of oxygen and redox sensing/regulatory system, elementary mode analysis was used to predict the metabolic potential of glycerol for succinate production by E. coli under either anaerobic or aerobic conditions. It was found that although the theoretical maximum succinate yields under both anaerobic and aerobic conditions are 1.0 mol/mol glycerol, the aerobic condition was considered to be more favorable for succinate production. Although increase of the oxygen concentration would reduce the succinate yield, the calculation suggests that controlling the molar fraction of oxygen to be under 0.65 mol/mol would be beneficial for increasing the succinate productivity. Based on the elementary mode analysis, the rational genetic modification strategies for efficient succinate production under aerobic and anaerobic conditions were obtained, respectively. Overexpressing the phosphoenolpyruvate carboxylase or heterogonous pyruvate carboxylase is considered to be the most efficient strategy to increase the succinate yield.

Here we propose, for the first time, a solar cell characterized by a semiconductor transistor structure (n/p/n or p/n/p) where the base-emitter junction is made of a high-bandgap semiconductor and the collector is made of a low-bandgap semiconductor. We calculate its detailed-balance efficiency limit and prove that it is the same one than that of a double-junction solar cell. The practical importance of this result relies on the simplicity of the structure that reduces the number of layers that are required to match the limiting efficiency of dual-junction solar cells without using tunnel junctions. The device naturally emerges as a three-terminal solar cell and can also be used as building block of multijunction solar cells with an increased number of junctions.

@@ Using the cascaded structure of a linear and a second-order nonlinear photonic crystals, we realize a high-efficiency optical parametric amplifier in the case of exact phase matching. This proposal is verified using the slow-envelope nonlinear finite difference time domain numerical method. Compared with the case of the individual nonlinear photonic crystal structure, the oscillation threshold is decreased obviously, and the peak power amplification factor of the transmitted signal is enhanced more than 20 times.

Two different nonfullerene acceptors and one copolymer are used to fabricate ternary organic solar cells (OSCs). The two acceptors show unique interactions that reduce crystallinity and form a homogeneous mixed phase in the blend film, leading to a high efficiency of ≈10.3%, the highest performance reported for nonfullerene ternary blends. This work provides a new approach to fabricate high-performance OSCs.

For all energy conversion systems that use any type of energy (mechanical, electrical, chemical, thermal) to produce a useful energy and a dissipated energy, it is shown that the optimum efficiency (which maximizes the useful power produced), is equal to half of the maximum efficiency (of the system which is supposed to be reversible). It is proposed to name this optimum efficiency 'Carnot efficiency' as a generalization of the case of the thermo-mechanical converter. (J.S.)

In comparison to in-pane sliding friction, rolling friction not only is likely to consume less mechanical energy but also presents high robustness with minimized wearing of materials. In this work, we introduce a highly efficient approach for harvesting mechanical energy based on rolling electrification and electrostatic induction, aiming at improving the energy conversionefficiency and device durability. The rolling triboelectric nanogenerator is composed of multiple steel rods sandwiched by two fluorinated ethylene propylene (FEP) thin films. The rolling motion of the steel rods between the FEP thin films introduces triboelectric charges on both surfaces and leads to the change of potential difference between each pair of electrodes on back of the FEP layer, which drives the electrons to flow in the external load. As power generators, each pair of output terminals works independently and delivers an open-circuit voltage of 425 V, and a short-circuit current density of 5 mA/m(2). The two output terminals can also be integrated to achieve an overall power density of up to 1.6 W/m(2). The impacts of variable structural factors were investigated for optimization of the output performance, and other prototypes based on rolling balls were developed to accommodate different types of mechanical energy sources. Owing to the low frictional coefficient of the rolling motion, an instantaneous energy conversionefficiency of up to 55% was demonstrated and the high durability of the device was confirmed. This work presents a substantial advancement of the triboelectric nanogenerators toward large-scope energy harvesting and self-powered systems.

The increased interest in the study of hydrocarbon utilizing microorganisms in recent years has been stimulated by the possibility of using their monooxygenases in the selective oxidation of aliphatic and aromatic compounds. As an example, long chain (>C16) n-alkanes are converted to dicarboxylic

(MMF) cladding. Our fabricated Photonic Lanterns are solid all-glass versions, with the MMF defined by a low-index tube surrounding the single-mode fibers (SMFs). We show experimentally that these devices can be used to achieve efficient and reversible coupling between a MMF and 61 SMFs, when perfectly...... matched launch conditions into the MMF are ensured. The total coupling loss from a 100 µm core diameter MM section to the ensemble of 61 SMFs and back to another 100 µm core MM section is measured to be as low as 0.76 dB. This demonstrates the feasibility of using the Photonic Lanterns within the field...

(MMF) cladding. Our fabricated Photonic Lanterns are solid all-glass versions, with the MMF defined by a low-index tube surrounding the single-mode fibers (SMFs). We show experimentally that these devices can be used to achieve efficient and reversible coupling between a MMF and 61 SMFs, when perfectly...... matched launch conditions into the MMF are ensured. The total coupling loss from a 100 µm core diameter MM section to the ensemble of 61 SMFs and back to another 100 µm core MM section is measured to be as low as 0.76 dB. This demonstrates the feasibility of using the Photonic Lanterns within the field...

This thesis work explores, experimentally, the potential gains in the conversionefficiency from ultra-intense laser light to proton beams using erbium hydride coatings. For years, it has been known that contaminants at the rear surface of an ultra-intense laser irradiated thin foil will be accelerated to multi-MeV. Inertial Confinement Fusion fast ignition using proton beams as the igniter source requires of about 1016 protons with an average energy of about 3MeV. This is far more than the 1012 protons available in the contaminant layer. Target designs must include some form of a hydrogen rich coating that can be made thick enough to support the beam requirements of fast ignition. Work with computer simulations of thin foils suggest the atomic mass of the non-hydrogen atoms in the surface layer has a strong affect on the conversionefficiency to protons. For example, the 167amu erbium atoms will take less energy away from the proton beam than a coating using carbon with a mass of 12amu. A pure hydrogen coating would be ideal, but technologically is not feasible at this time. In the experiments performed for my thesis, ErH3 coatings on 5 μm gold foils are compared with typical contaminants which are approximately equivalent to CH1.7. It will be shown that there was a factor of 1.25 ± 0.19 improvement in the conversionefficiency for protons above 3MeV using erbium hydride using the Callisto laser. Callisto is a 10J per pulse, 800nm wavelength laser with a pulse duration of 200fs and can be focused to a peak intensity of about 5 x 1019W/cm2. The total number of protons from either target type was on the order of 1010. Furthermore, the same experiment was performed on the Titan laser, which has a 500fs pulse duration, 150J of energy and can be focused to about 3 x 1020 W/cm2. In this experiment 1012 protons were seen from both erbium hydride and

Wavelength Raman converters have been developed for years to provide an elegant solution to easily shift the wavelength of existing lasers. In the pulse regime, due to relatively low Raman gains, these converters are usually limited to high-energy pulses, typically a few J or a few mJ in the nanosecond or picosecond regime. In order to build efficient Raman converters with lower energy pulses, we have developed a new class of fiber wavelength shifters based on Stimulated Raman Scattering in the liquid filling the hollow core of photonic bandgap fibers or Kagome fibers. The liquid choice, the design of the photonic crystal microstructure, the fiber length and its diameter give us enough degrees of freedom to realize efficient and versatile shifters, each being optimized for a specific wavelength shift. Connecting such a fiber device to a fixed wavelength laser allows delivering a new wavelength. With the same laser, another wavelength can be obtained by connecting another shifter. Using microlasers delivering 532 nm sub-nanosecond pulses of about 1 μJ, we already built a full series of shifters to reach any wavelength among: 556 nm; 561 nm; 582 nm; 595 nm; 612 nm; 630 nm; 650 nm; 667 nm; 772 nm. Hereafter, we detail how we design and optimize these new devices.

Solid-phase extraction is one of the most important techniques for sample purification and concentration. A wide variety of solid phases have been used for sample preparation over time. In this work, the efficiency of a new kind of solid-phase extraction adsorbent, which is a microporous material made from modified cyclodextrin bounded to a silica network, is evaluated through an analytical method which combines solid-phase extraction with high-performance liquid chromatography to determine polycyclic aromatic hydrocarbons in water samples. Several parameters that affected the analytes recovery, such as the amount of solid phase, the nature and volume of the eluent or the sample volume and concentration influence have been evaluated. The experimental results indicate that the material possesses adsorption ability to the tested polycyclic aromatic hydrocarbons. Under the optimum conditions, the quantification limits of the method were in the range of 0.09-2.4μgL(-1) and fine linear correlations between peak height and concentration were found around 1.3-70μgL(-1). The method has good repeatability and reproducibility, with coefficients of variation under 8%. Due to the concentration results, this material may represent an alternative for trace analysis of polycyclic aromatic hydrocarbons in water trough solid-phase extraction.

In this present contribution, AMPS-1D device simulator is employed to study the performances of superstrate SLG/TCO/p-Cu(In,Ga)Se2(CIGS)/n-ODC/n-In2Se3/Metal thin film solar cells. The impact of the TCO and Metal work functions on the cell performance has been investigated. The combination of optical transparency and electrical property for TCO front contact layer is found to yield high efficiency. The obtained results show that the TCO work function should be large enough to achieve high conversionefficiency for superstrate CIGS solar cell. Nevertheless, it is desirable for Metal back contact layer to have low work function to prevent the effect of band bending in the n-In2Se3/Metal interface. Several TCOs materials and metals have been tested respectively as a front and back contact layers for superstrate CIGS solar cells. An efficiency of 20.18%, with Voc ≈ 0.71 V, Jsc ≈ 35.36 mA/cm2 and FF ≈ 80.42%, has been achieved with ZnSn2O3-based as TCO front contact layer. In the case of SnO2:F front contact and indium back contact layers, an efficiency of 16.31%, with Voc ≈ 0.64 V, Jsc ≈ 31.4 mA/cm2 and FF ≈ 79.4%, has been obtained. The present results of simulation suggest an improvement of superstrate CIGS solar cells efficiency for feasible fabrication.

We present a numerical approach that, in conjunction with a fully set up Dynamic Energy Budget (DEB) model, aims at consistently approximating the feeding history of cultivated fish from the commonly measured aquaculture data (body length, body mass, or the condition factor). We demonstrate the usefulness of the approach by performing validation of a DEB-based model for Pacific bluefin tuna (Thunnus orientalis) on an independent dataset and exploring the implied bioenergetics of this species in captivity. In the context of validation, the results indicate that the model successfully accounts for more than 75% of the variance in actual fish feed. At the 5% significance level, predictions do not underestimate nor overestimate observations and there is no bias. The overall model accuracy of 87.6% is satisfactory. In the context of tuna bioenergetics, we offer an explanation as to why the first reproduction in the examined case occurred only after the fish reached seven years of age, whereas it takes five years in the wild and sometimes as little as three years in captivity. Finally, we calculate energy conversionefficiencies and the supply stress throughout the entire lifetime to theoretically underpin the relatively low contribution of growth to aerobic metabolism implied by respirometry and high feed conversion ratio observed in bluefin tuna aquaculture.

Dye-sensitized solar cells (DSSCs) are fabricated based on anatase TiO(2) nanosheets (TiO(2)-NSs) with exposed {001} facets, which were obtained by a simple one-pot hydrothermal route using HF as a morphology controlling agent and Ti(OC(4)H(9))(4) as precursor. The prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis absorption spectroscopy and N(2) adsorption-desorption isotherms. The photoelectric conversion performances of TiO(2)-NSs solar cells are also compared with TiO(2) nanoparticles (TiO(2)-NPs) and commercial-grade Degussa P25 TiO(2) nanoparticle (P25) solar cells at the same film thickness, and their photoelectric conversionefficiencies (η) are 4.56, 4.24 and 3.64%, respectively. The enhanced performance of the TiO(2)-NS solar cell is due to their good crystallization, high pore volume, large particle size and enhanced light scattering. The prepared TiO(2) nanosheet film electrode should also find wide-ranging potential applications in various fields including photocatalysis, catalysis, electrochemistry, separation, purification and so on.

Dye-sensitized solar cells (DSSCs) are fabricated based on anatase TiO2 nanosheets (TiO2-NSs) with exposed {001} facets, which were obtained by a simple one-pot hydrothermal route using HF as a morphology controlling agent and Ti(OC4H9)4 as precursor. The prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis absorption spectroscopy and N2 adsorption-desorption isotherms. The photoelectric conversion performances of TiO2-NSs solar cells are also compared with TiO2 nanoparticles (TiO2-NPs) and commercial-grade Degussa P25 TiO2 nanoparticle (P25) solar cells at the same film thickness, and their photoelectric conversionefficiencies (η) are 4.56, 4.24 and 3.64%, respectively. The enhanced performance of the TiO2-NS solar cell is due to their good crystallization, high pore volume, large particle size and enhanced light scattering. The prepared TiO2 nanosheet film electrode should also find wide-ranging potential applications in various fields including photocatalysis, catalysis, electrochemistry, separation, purification and so on.

Full Text Available The modern software defined radios (SDRs use complex signal processing algorithms to realize efficient wireless communication schemes. Several such algorithms require a specific symbol to sample ratio to be maintained. In this context the fractional rate converter (FRC becomes a crucial block in the receiver part of SDR. The paper presents an area optimized dynamic FRC block, for low power SDR applications. The limitations of conventional cascaded interpolator and decimator architecture for FRC are also presented. Extending the SINC function interpolation based architecture; towards high area optimization and providing run time configuration with time register are presented. The area and speed analysis are carried with Xilinx FPGA synthesis tools. Only 15% area occupancy with maximum clock speed of 133 MHz are reported on Spartan-6 Lx45 Field Programmable Gate Array (FPGA.

Various tandem cell configurations have been reported for highly efficient and spontaneous hydrogen production from photoelectrochemical solar water splitting. However, there is a contradiction between two main requirements of a front photoelectrode in a tandem cell configuration, namely, high transparency and high photocurrent density. Here we demonstrate a simple yet highly effective method to overcome this contradiction by incorporating a hybrid conductive distributed Bragg reflector on the back side of the transparent conducting substrate for the front photoelectrochemical electrode, which functions as both an optical filter and a conductive counter-electrode of the rear dye-sensitized solar cell. The hybrid conductive distributed Bragg reflectors were designed to be transparent to the long-wavelength part of the incident solar spectrum (λ>500 nm) for the rear solar cell, while reflecting the short-wavelength photons (λ<500 nm) which can then be absorbed by the front photoelectrochemical electrode for enhanced photocurrent generation.

A review of three-phase PWM converter topologies which do show a low complexity/high reliability and high efficiency and power density and are therefore of main interest for a future industrial application is presented.A three-switch/level Boost-type PWM rectifier (VIENNA Rectifier),a Buck+Boost-type PWM rectifier with wide output voltage range and the AC/AC Sparse Matrix Converter concept are discussed in detail and topics to be treated in the course of further research are identified. Finally,it is shown how the aspects being relevant for the realization of highly compact converter systems could be integrated into education in the field.

Optical spectrum splitting systems that divide light between independent solar cells of different band gaps have received increasing attention in recent years as an alternative to expensive multijunction cells for high-efficiency PV. Most research, however, has focused on dichroic filters and other photonic structures that are expensive to manufacture. This has the effect of transferring the cost of the system from the PV cells to the optics. As a low-cost spectrum splitting approach we designed a prismatic lens that simultaneously splits and concentrates light and can be fabricated by injection molding. We present experimental results of a two-cell demonstration system, and calculations for low-cost configurations of commercial solar cells, enabled by the removal of lattice-matching requirements.

The screen-printing method is an economical metallization technique used by most manufacturers of conventional silicon solar cells. This method limits the cells' use under concentrated light owing to high series resistance losses caused, among other reasons, by low metal density in the fingers. This paper describes increasing the finger metal density by electrolytic deposition. The electrolytic deposition of silver is an economical, controllable and readily commercializable deposition method to reduce the front and back metallization series resistance contributions. With an optimized grid design, compatible with 1 sun silicon cell technology, and later electrolytic silver deposition we have obtained cells that maintain their efficiency up to 15 suns. In addition, an analysis of the performance of these cells under uniform and non-uniform illumination were carried out on n{sup +}p and n{sup +}pn{sup +} structures. (author)

We propose a spoof surface plasmon polariton (SPP) emitter which is composed of ultrathin corrugated metallic strips, exhibiting the directional radiation property. The spoof SPP emitter provides a way to quickly convert the SPP mode to a radiated mode. By controlling phase modulations produced by the phase-gradient metasurface on the ultrathin metallic strips, we demonstrate theoretically and experimentally that spoof SPP waves are converted into spatial propagating waves with high efficiency, which are further radiated with flexible beam steering. The proposed method sets up a link between SPP waves and radiation waves in a highly controllable way, which would possibly open an avenue in designing new kinds of microwave and optical elements in engineering.

Recently updated nanocrystalline soft magnetic Fe-Co-Si-B-P-Cu alloys "NANOMET®" exhibit high saturation magnetic flux density (Bs > 1.8 T), low coercivity (Hc DC motor using NANOMET® core exhibited remarkable improvement in energy consumption. The prototype motor with an outer core diameter of 70 mm and a core thickness of 50 mm was constructed using laminated nano-crystallized NANOMET® ribbons. Core-loss for the constructed motor was improved from 1.4 W to 0.4 W only by replacing the non-oriented Si-steel core with NANOMET® one. The overall motor efficiency is evaluated to be 3% improvement. In this work, the relation between processing and resulting magnetic properties will be presented. In addition, feasibility for commercialization will also be discussed.

We describe the colloidal hot-injection synthesis of phase-pure nanocrystals (NCs) of a highly abundant mineral, chalcopyrite (CuFeS2). Absorption bands centered at around 480 and 950 nm, spanning almost the entire visible and near infrared regions, encompass their optical extinction characteristics. These peaks are ascribable to electronic transitions from the valence band (VB) to the empty intermediate band (IB), located in the fundamental gap and mainly composed of Fe 3d orbitals. Laser-irradiation (at 808 nm) of an aqueous suspension of CuFeS2 NCs exhibited significant heating, with a photothermal conversionefficiency of 49%. Such efficient heating is ascribable to the carrier relaxation within the broad IB band (owing to the indirect VB-IB gap), as corroborated by transient absorption measurements. The intense absorption and high photothermal transduction efficiency (PTE) of these NCs in the so-called biological window (650-900 nm) makes them suitable for photothermal therapy as demonstrated by tumor ce...

The recent development of 2D monolayer lateral semiconductor has created new paradigm to develop p-n heterojunctions. Albeit, the growth methods of these heterostructures typically result in alloy structures at the interface, limiting the development for high-efficiency photovoltaic (PV) devices. Here, the PV properties of sequentially grown alloy-free 2D monolayer WSe-MoS lateral p-n heterojunction are explores. The PV devices show an extraordinary power conversionefficiency of 2.56% under AM 1.5G illumination. The large surface active area enables the full exposure of the depletion region, leading to excellent omnidirectional light harvesting characteristic with only 5% reduction of efficiency at incident angles up to 75°. Modeling studies demonstrate the PV devices comply with typical principles, increasing the feasibility for further development. Furthermore, the appropriate electrode-spacing design can lead to environment-independent PV properties. These robust PV properties deriving from the atomically sharp lateral p-n interface can help develop the next-generation photovoltaics.

Large-scale, subwavelength-structured nanodome arrays were successfully fabricated using simple, scalable bottom-up colloidal (nanosphere) lithography on a glass substrate as an efficient antireflective photoanode for dye-sensitized solar cells (DSSCs). A self-assembled monolayer of close-packed colloidal crystals (silica) was used as a structural template to pattern the two-dimensional subwavelength-structured nanodome arrays, which function as an efficient antireflective coating due to the graded refractive index across the interface between the air and specific nanodome array structure. The light harvesting for a DSSC with a subwavelength-structured antireflective coating was enhanced due to the improved broadband antireflectivity. Adjusting the nanodome size yielded a short-circuit current density (JSC) of 15.88 mA/cm2 with a power conversionefficiency (PCE) of 8.82%, which were both better than the reference cell without a subwavelength-structured antireflective coating (JSC = 15.26 mA/cm2 and PCE = 8.45%).

Photocatalytic water splitting using particulate semiconductors is a potentially scalable and economically feasible technology for converting solar energy into hydrogen. Z-scheme systems based on two-step photoexcitation of a hydrogen evolution photocatalyst (HEP) and an oxygen evolution photocatalyst (OEP) are suited to harvesting of sunlight because semiconductors with either water reduction or oxidation activity can be applied to the water splitting reaction. However, it is challenging to achieve efficient transfer of electrons between HEP and OEP particles. Here, we present photocatalyst sheets based on La- and Rh-codoped SrTiO3 (SrTiO3:La, Rh; ref. ) and Mo-doped BiVO4 (BiVO4:Mo) powders embedded into a gold (Au) layer. Enhancement of the electron relay by annealing and suppression of undesirable reactions through surface modification allow pure water (pH 6.8) splitting with a solar-to-hydrogen energy conversionefficiency of 1.1% and an apparent quantum yield of over 30% at 419 nm. The photocatalyst sheet design enables efficient and scalable water splitting using particulate semiconductors.

Photocatalytic water splitting using particulate semiconductors is a potentially scalable and economically feasible technology for converting solar energy into hydrogen. Z-scheme systems based on two-step photoexcitation of a hydrogen evolution photocatalyst (HEP) and an oxygen evolution photocatalyst (OEP) are suited to harvesting of sunlight because semiconductors with either water reduction or oxidation activity can be applied to the water splitting reaction. However, it is challenging to achieve efficient transfer of electrons between HEP and OEP particles. Here, we present photocatalyst sheets based on La- and Rh-codoped SrTiO3 (SrTiO3:La, Rh; ref. ) and Mo-doped BiVO4 (BiVO4:Mo) powders embedded into a gold (Au) layer. Enhancement of the electron relay by annealing and suppression of undesirable reactions through surface modification allow pure water (pH 6.8) splitting with a solar-to-hydrogen energy conversionefficiency of 1.1% and an apparent quantum yield of over 30% at 419 nm. The photocatalyst sheet design enables efficient and scalable water splitting using particulate semiconductors.

Band gap narrowing is important for applications of ZnO, especially for photoelectrochemical water splitting. In this work, we carried out first-principles electronic structure calculations with a hybrid density functional on defected ZnO. It is found that nitrogen substitutional doping alone cannot explain the largely enhanced conversionefficiency observed in nitrogen doped ZnO. Instead, complex defects formed by substitutional nitrogen and intrinsic defects play an important role in the band gap narrowing, in agreement with recent experimental results. We propose ZnO fabricated in a Zn-rich environment with heavy nitrogen doping as a photocatalyst for hydrogen generation from water splitting. A method for controlling the band gap of ZnO is also proposed.

Anodically fabricated tantalum oxide (Ta2O5) nanorod array carpets are converted into the corresponding tantalum oxynitride (TaON) through nitridation in an ammonia atmosphere. The measured optical bandgap energy of TaON is ∼2.3 eV, which is also confirmed via the density functional theory calculations. When used to photoelectrochemically split water (AM 1.5G illumination, 1 M KOH, and 0.6 V applied DC bias), the multilayer nanorod films show visible-light incident photon conversionefficiencies (IPCE) as high as 7.5%. The enhanced photochemical activity is discussed in terms of the ordered one-dimensional morphology as well as the electron effective mass in TaON and Ta2O5.

Recent years have seen a resurgence of interest in crystalline silicon Schottky junction solar cells distinguished by the use of low density of electronic states (DOS) nanocarbons (nanotubes, graphene) as the metal contacting the Si. Recently, unprecedented modulation of the power conversionefficiency in a single material system has been demonstrated in such cells by the use of electronic gating. The gate field induced Fermi level shift in the low-DOS carbon serves to enhance the junction built-in potential, while a gate field induced inversion layer at the Si surface, in regions remote from the junction, keeps the photocarriers well separated there, avoiding recombination at surface traps and defects (a key loss mechanism). Here, we extend these results into the third dimension of a vertical Si nanowire array solar cell. A single wall carbon nanotube layer engineered to contact virtually each n-Si nanowire tip extracts the minority carriers, while an ionic liquid electrolytic gate drives the nanowire body into inversion. The enhanced light absorption of the vertical forest cell, at 100 mW/cm(2) AM1.5G illumination, results in a short-circuit current density of 35 mA/cm(2) and associated power conversionefficiency of 15%. These results highlight the use of local fields as opposed to surface passivation as a means of avoiding front surface recombination. A deleterious electrochemical reaction of the silicon due to the electrolyte gating is shown to be caused by oxygen/water entrained in the ionic liquid electrolyte. While encapsulation can avoid the issue, a nonencapsulation-based approach is also implemented.

In the Ni-substituted chlorophylls, an ultrafast (chlorophylls, experimentally, using time-resolved laser-induced optoacoustic spectroscopy, and theoretically, using group theory approach. The Ni-substituted chlorophylls show exceptional photostability and the optoacoustic measurements confirm the prompt and very efficient (100%) excitation-into-heat conversion in these complexes. Considering their excellent spectral properties and the loss-free excitation-into-heat conversion they are likely to become a new class of versatile photocalorimetric references. The curious features of the Ni-substituted chlorophylls originate from the symmetry of a ligand field created in the central cavity. The central N-Ni(2+) bonds, formed via the donation of two electrons from each of the sp(2) orbitals of two central nitrogens to an empty [Formula: see text] hybrid centered on Ni(2+), have a considerable covalent character. The extreme rate of excited state relaxation is then not due to a ladder of the metal centered d-states, often invoked in metalloporphyrins, but seems to result from a peculiar topology of the potential energy surface (a saddle-shaped crossing) due to the covalent character of the N-Ni(2+) bonds. This is confirmed by a strong 0→0 character of electronic transitions in these complexes indicating a similarity of their equilibrium geometries in the ground (S(0)) and the excited states (both Q(X) and Q(Y)). The excitation energy is very efficiently converted into molecular vibrations and dissipated as heat, involving the central Ni(2+). These Ni-substituted pigments pose a fine exemplification of symmetry control over properties of excited states of transition metal complexes.

-- The food consumption and ecological conversionefficiency of a species marine pelagic and small size fish, Hyporhamphus sajori, were determined by using in situ stomach content method presented by Eggers. The results showed that: (1) the fish was taken in food all day, so empty-stomach rate was very low, taking up about 4.5% of the total determined fish number. However, the fish still has significant daily feeding rhythm. A feeding peak was found 0: 00 o' clock at night, but feeding level was always high in the daytime; (2) relationship between instantaneous food content in stomach and corresponding time could be described as St = a@ e- b@t. There was not significant difference of instantaneous gastric evacuation rate between two determinations, with average value being 0.13 × 10- 2g/ (g@h) (wet weight); (3) the daily food consumption tended to change in irregular waving form, with average value being (10.16 × 10-2 ± 1.19 × 10-2) g/ (g@ d) (wet weight) or (55.56 × 10-2 ± 6.51 ×10-2) kJ/ (g@d). The wave distance is constant and about 14 d, but the wave height changed largely;(4) actual determining value of daily growth rate was 3.24× 10-2g/ (g@d) (wet weight) or 12.91 ×10-2kJ/ (g@d), from which 31.89% (wet weight) or 23.24% kJ of ecological conversionefficiency could be obtained.

Full Text Available The main objective of the present work was to assess and compare the wave power resources in various offshore and nearshore areas. From this perspective, three different groups of coastal environments were considered: the western Iberian nearshore, islands and an enclosed environment with sea waves, respectively. Some of the most representative existent wave converters were evaluated in the analysis and a second objective was to compare their performances at the considered locations, and in this way to determine which is better suited for potential commercial exploitation. In order to estimate the electric power production expected in a certain location, the bivariate distributions of the occurrences corresponding to the sea states, defined by the significant wave height and the energy period, were constructed in each coastal area. The wave data were provided by hindcast studies performed with numerical wave models or based on measurements. The transformation efficiency of the wave energy into electricity is evaluated via the load factor and also through the capture width, defined as the ratio between the electric power estimated to be produced by each specific wave energy converters (WEC and the expected wave power corresponding to the location considered. Finally, by evaluating these two different indicators, comparisons of the performances of three WEC types (Aqua Buoy, Pelamis and Wave Dragon in the three different groups of coastal environments considered have been also carried out. The work provides valuable information related to the effectiveness of various technologies for the wave energy extraction that would operate in different coastal environments.

We demonstrate the fabrication of a multi-mode (MM) to 61 port single-mode (SM) splitter or "Photonic Lantern". Low port count Photonic Lanterns were first described by Leon-Saval et al. (2005). These are based on a photonic crystal fiber type design, with air-holes defining the multi-mode fiber (MMF) cladding. Our fabricated Photonic Lanterns are solid all-glass versions, with the MMF defined by a low-index tube surrounding the single-mode fibers (SMFs). We show experimentally that these devices can be used to achieve efficient and reversible coupling between a MMF and 61 SMFs, when perfectly matched launch conditions into the MMF are ensured. The total coupling loss from a 100 μm core diameter MM section to the ensemble of 61 SMFs and back to another 100 μm core MM section is measured to be as low as 0.76 dB. This demonstrates the feasibility of using the Photonic Lanterns within the field of astrophotonics for coupling MM star-light to an ensemble of SM fibers in order to perform fiber Bragg grating based spectral filtering.

Methanol has been converted to hydrocarbons over conventional and mesoporous H-ZSM-5 and H-Ga-MFI. The gallium based zeotypes are analogous to H-ZSM-5, but the Brønsted acidity is introduced by framework incorporation of gallium rather than aluminum, which leads to lower intrinsic acid strength. ...... (hydrolysis) of the Ga&sbnd;O bonds in the zeolite structure rather than coke deposition....

availability. Fuel independence would alleviate uncertainties in the world market supply of oil along with commercial fluctuations in price. In addition...this supply by supporting the development of synthetic hydrocarbon fuel from the vast natural resources, such as coal, shale, gas hydrates, and CO2...product a day by steam-reforming coal to generate syngas for the FT process.5 A water-gas shift is needed to obtain a 2:1 ratio of hydrogen/carbon

Non-silicide PV cell structures were successfully applied to the photovoltaic (PV)-assisted UHF rectifier, which is one example realization of the “synergistic ambient energy harvesting” concept. Silicide blocking of PV cell area was experimentally verified to be effective for increasing photo-generated bias voltage, which resulted in the improved power conversionefficiency (PCE) of the rectifier by enhanced VTH compensation effect. Increase in both transparency of light and quantum efficiency of PV cells obtained by eliminating silicide layer affects the PCE improvement almost equally. 25.8% of PCE was achieved under the conditions of an RF input power of -20 dBm, a frequency of 920 MHz, an output load of 47 kΩ, and a typical indoor light irradiance level of 1 W/m2. In addition, when the non-silicide PV cell technique was applied to the voltage-boosted PV-cell structures, 32.1% peak PCE was achieved at 10 W/m2.

Full Text Available For lower reflectance, we applied a maskless plasma texturing technique using reactive ion etching (RIE on acidic-textured multicrystalline silicon (mc-Si wafer. RIE texturing had a deep and narrow textured surface and showed excellent low reflectance. Due to plasma-induced damage, unless the RIE-textured surfaces have the proper damage removal etching (DRE, they have a drop in V oc and FF. RIE texturing with a proper DRE had sufficiently higher short circuit current (Isc than acidic-textured samples without a drop in open circuit voltage (V oc . And in order to improve efficiency of mc-Si solar cell, we applied RIE texturing with optimized DRE condition to selective emitter structure. In comparison with the acidic-textured solar cells, RIE-textured solar cells have above 200 mA absolute gain in Isc. And optimized RIE samples with a DRE by HNO3/HF mixture showed 17.6% conversionefficiency, which were made using an industrial screen printing process with selective emitter structure.

This work demonstrates the enhanced power conversionefficiency (PCE) in InGaN/GaN multiple quantum well (MQWs) solar cells with gradually decreasing indium composition in quantum wells (GQWs) toward p-GaN as absorber. The GQW can improve the fill factor from 42% to 62% and enhance the short current density from 0.8 mA/cm2 to 0.92 mA/cm2, as compares to the typical MQW solar cells. As a result, the PCE is boosted from 0.63% to 1.11% under AM1.5G illumination. Based on simulation and experimental results, the enhanced PCE can be attributed to the improved carrier collection in GQW caused by the reduction of potential barriers and piezoelectric polarization induced fields near the p-GaN layer. The presented concept paves a way toward highly efficient InGaN-based solar cells and other GaN-related MQW devices.

Full Text Available Bangladesh is endowed with people along with limited primary energy sources and low electrification rate. Most of the hilly areas are out of the coverage of national grid where tribal people, a significant part of the country, are dwelling. The economic development of the whole country depends upon their advancement which is related to the electrification rate. Available micro hydro potential in hilly region could be a solution for this crisis if modified design is used. This paper deals with a new design of water power potential conversionefficiency increment of a micro hydro power plant to 95% from about 50% by using solar power for heating the water. In this proposed hybrid design, a parabolic reflector is considered to be used after comparative solar intensity analysis on different micro hydro power sites in Bangladesh to increase the velocity as well as the flow rate through penstock by heating the water to increase power production and efficiency. The main purpose of this concept is to supply electricity to more people, especially, remote tribal community by available renewable energy sources for economic development.

A highly efficient third generation catalyst, CaCu3Ti4O12 (CCTO) shows excellent photoelectrochemical (PEC) and photocatalytic ability. As only 4% part of the solar spectrum covers UV light, thus it is highly desirable to develop visible light active photocatalyst materials like CCTO for effective solar energy conversion. A direct band transition with a narrow band gap (1.5 eV) was observed. Under light irradiation, high photocurrent density was found to be 0.96 mA/cm2, indicating the visible light induced photocatalytic ability of CCTO. Visible light mediated photocatalytic and photoelectrocatalytic degradation efficiency of CaCu3Ti4O12 pellets (CCTO) was investigated for three classes of pharmaceutical waste: erythrosin (dye), ciprofloxacin (antibiotic) and estriol (steroid). It is found that the degradation process follows first order kinetic reaction in electrocatalysis, photocatalysis and photoelectrocatalysis and high kinetic rate constant was observed in photoelectrocatalysis. This was quite high in comparison to previously reported methods. PMID:26725655

The realization of controllable morphologies of bulk heterojunctions (BHJ) in organic photovoltaics (OPVs) is one of the key factors enabling high-efficiency devices. We provide new insights into the fundamental mechanisms essential for the optimization of power conversionefficiencies (PCEs) with additive processing to PBDTTT-CF:PC71BM system. We have studied the underlying mechanisms by monitoring the 3D nanostructural modifications in BHJs and correlated the modifications with the optical analysis and theoretical modeling of charge transport. Our results demonstrate profound effects of diiodooctane (DIO) on morphology and charge transport in the active layers. For small amounts of DIO (3 vol %), DIO facilitates a loosely packed mixed morphology with large clusters of PC71BM, leading to deterioration in PCE. Theoretical modeling of charge transport reveals that DIO increases the mobility of electrons and holes (the charge carriers) by affecting the energetic disorder and electric field dependence of the mobility. Our findings show the implications of phase separation and carrier transport pathways to achieve optimal device performances.

The performance of solar-thermal conversion systems can be improved by incorporation of nanocarbon-stabilized microencapsulated phase change materials (MPCMs). The geometry of MPCMs in the microcapsules plays an important role for improving their heating efficiency and reliability. Yet few efforts have been made to critically examine the formation mechanism of different geometries and their effect on MPCMs-shell interaction. Herein, through changing the cooling rate of original emulsions, we acquire MPCMs within the nanocarbon microcapsules with a hollow structure of MPCMs (h-MPCMs) or solid PCM core particles (s-MPCMs). X-ray photoelectron spectroscopy and atomic force microscopy reveals that the capsule shell of the h-MPCMs is enriched with nanocarbons and has a greater MPCMs-shell interaction compared to s-MPCMs. This results in the h-MPCMs being more stable and having greater heat diffusivity within and above the phase transition range than the s-MPCMs do. The geometry-dependent heating efficiency and system stability may have important and general implications for the fundamental understanding of microencapsulation and wider breadth of heating generating systems.

Micro methanol-steam reformer for fuel cell can effectively produce hydrogen as reforming response to steam takes place in low temperature (less than 250℃). This study conducted numerical research on this reformer. First, study set wall temperature of the reformer at 100, 140, 180 and 220℃ while methanol conversionefficiency was set in 0, 0.072, 3.83 and 46.51% respectively. Then, porosity of catalyst was set in 0.1, 0.35, 0.6 and 0.85 and although there was no significant difference in methanol conversionefficiency, values of pressure drop were 4645.97, 59.50, 5.12 and 0.45 kPa respectively. This study verified that methanol-steam reformer rarely responds under the temperature of 180℃ and porosity does not have much effect on methanol conversionefficiency if the fluid flowing through reformer lowers activation energy by sufficiently contacting reformer.

The efficiency of thermoelectric conversion of heat from gas combustion was evaluated in a small-scale system consisting of two channels with opposing gas flows and thermocouples located in the separating wall. Combustion occurred in the chamber fed with fresh mixture heated by combustion products through heat-conducting walls of the channel. In the channel walls, there were thermoelectric converters. It has been shown that in this system, the maximum conversionefficiency of heat from gas combustion may be close to the maximum efficiency of thermoelectric conversion calculated by the maximum acceptable working temperature of the hot side of the converter. This conclusion is valid in the case when the adiabatic combustion temperature of the gas mixture is below the maximum allowable operating temperature of the hot side of the thermoelectric converter. The considered system is promising for the burning of low-calorific gas mixtures and does not require additional energy for cooling the cold side of the thermoelectric converter.

It is an important approach to improve the x-ray conversionefficiency of laser-ablated high-Z plasmas by using low initial density materials for various applications. However, unavoidable low-Z impurities in the manufacture process of low-density high-Z foam targets will depress this effect. A general easy-to-use analytical model based on simulations was developed to evaluate the quantitative impact of impurities within the gold foam target on laser to x-ray conversionefficiency. In addition, the x-ray conversionefficiencies of 1 g/cm3 gold foams with two different initial contents of impurities were experimentally investigated. Good agreements have been achieved between the model results and experiments.

Although new optical materials continue to open up access to more and more wavelength bands where femtosecond laser pulses can be generated, light frequency conversion techniques are still indispensable in filling the gaps on the ultrafast spectral scale. With high repetition rate, low pulse energy laser sources (oscillators) tight focusing is necessary for a robust wave mixing and the efficiency of broadband nonlinear conversion is limited by diffraction as well as spatial and temporal walk-off. Here we demonstrate a miniature third harmonic generator (tripler) with conversionefficiency exceeding 30%, producing 246 fs UV pulses via cascaded second order processes within a single laser beam focus. Designing this highly efficient and ultra compact frequency converter was made possible by full 3-dimentional modelling of propagation of tightly focused, broadband light fields in nonlinear and birefringent media. PMID:28225007

Although new optical materials continue to open up access to more and more wavelength bands where femtosecond laser pulses can be generated, light frequency conversion techniques are still indispensable in filling the gaps on the ultrafast spectral scale. With high repetition rate, low pulse energy laser sources (oscillators) tight focusing is necessary for a robust wave mixing and the efficiency of broadband nonlinear conversion is limited by diffraction as well as spatial and temporal walk-off. Here we demonstrate a miniature third harmonic generator (tripler) with conversionefficiency exceeding 30%, producing 246 fs UV pulses via cascaded second order processes within a single laser beam focus. Designing this highly efficient and ultra compact frequency converter was made possible by full 3-dimentional modelling of propagation of tightly focused, broadband light fields in nonlinear and birefringent media.

Full Text Available Melanocortin-4 receptor (MC4R gene is part of the central melanocortin pathway located in the hypothalamus, an area of the brain in which appetite is regulated. Insulin-like growth factor 2 (IGF2 gene plays a role in muscle growth, myoblast proliferation and differentiation. Thus, they are candidate genes for feed conversionefficiency (FCE. The study was to investigate the effects of variants in cattle MC4R and IGF2 gene on FCE traits including residual feed intake (RFI, feed conversion ratio (FCR and average daily gain (ADG. We screened single nucleotide polymorphisms (SNPs of the two genes in 118 Simmental bulls by DNA-pool sequencing and genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS analysis. C1069G locus of MC4R and four SNPs (C2209T, G18587C, A22950T and G26920T of IGF2 were identified in the population. The χ2 test showed that only MC4R-C1069G, IGF2-C2209T and IGF2-G18587C loci fitted with Hardy-Weinberg equilibrium (P>0.05. General linear model (GLM was used to analyze differences between genotypes. The results showed that only IGF2-G18587C locus has a significant effect on ADG (P0.05. CC and GG genotypes were the dominant genotypes; individual with CC or GG genotype had a larger ADG than GC (P<0.05.

Ethane and methanol are converted simultaneously over Ga/H-ZSM-5, Mo/H-ZSM-5 and Ga-Mo/H-ZSM-5 to produce light olefins and aromatics. The presence of methanol in the reactant stream is intended to facilitate activation of ethane following literature reports on co-conversion of methane and methanol....... However, the conversion of ethane actually decreases significantly when methanol is present. To gain insight into mechanistic details, C-13-labeled methanol is co-converted with unlabeled ethane. These isotopic labeling studies show that carbon atoms from ethane and methanol are mixed in the products...

The present study describes the kinetics of syngas transformation into liquid hydrocarbons (boiling point in the gasoline range) using as catalyst a mixture of a metallic component, Cr{sub 2}O{sub 3}-ZnO, and of an acidic component, ZSM-5 zeolite. Experimental results were obtained in an isothermal fixed-bed integral reactor. The validity of several kinetic models, available for methanol synthesis, is analysed and modifications are proposed. These changes involve a rate equation with a CO{sub 2} concentration-dependent term. Catalyst deactivation is also evaluated and the effect of the operating conditions on coke deposition is established. Moreover, the rate of CO conversion and the change of catalytic activity with time-on-stream were described using a kinetic model showing a weak influence of temperature. (Author)

Natural gas is not only playing an increasing important role in energy and chemicals supplies in 21st century but is also the second most important component of the greenhouse gases. Clean and direct conversion of methane to C2 hydrocarbons (ethane, ethene and acetylene) through AC and DC plasma catalysis enhanced by electric field was studied at low temperature ranging from 50?℃ to 100?℃, atmospheric pressure and low power conditions. The influence of form of the electrode, distance between the electrodes, voltage, diameter of reactor, flow of inlet methane, N2/CH4(mole) and 20 catalysts were tested under low temperature plasma. The results indicated that best form of the electrode was plate; the better distance between the electrode was 5mm; the appropriate voltage was 38V(AC);the apparent diameter of reactor was 17mm, the likely flow range flux of inlet methane was 60—80?ml*min-1, the suitable ratio of N2/CH4 (mole) was 0.5—1.0.The yield of C2 hydrocarbons was the highest on V2O5，ZnO(5%)/ZSM-5-38 catalyst, the yield of ethene was the highest on La0.8Sr0.2CrO3，ZnO catalyst. The results are better than those obtained through conventional reaction of oxidation coupling of methane.

For its unique position in the coal chemical industry, the methanol to olefin (MTO) reaction has been a hot topic in zeolite catalysis. Due to the complexities of catalyst structure and reaction networks, many questions such as how the olefin chain is built from methanol remain elusive. On the basis of periodic density functional theory calculations, this work establishes the first complete catalytic cycle for MTO reaction via hexamethylbenzene (HMB) trapped in HSAPO-34 zeolite based on the so-called side chain hydrocarbon pool mechanism. The cycle starts from the methylation of HMB that leads to heptamethylbenzenium ion (heptaMB{sup +}) intermediate. This is then followed by the growth of side chain via repeated deprotonation of benzenium ions and methylation of the exocyclic double bond. Ethene and propene can finally be released from the side ethyl and isopropyl groups of benzenium ions by deprotonation and subsequent protonation steps. We demonstrate that (i) HMB/HSAPO-34 only yields propene as the primary product based on the side chain hydrocarbon pool mechanism and (ii) an indirect proton-shift step mediated by water that is always available in the system is energetically more favorable than the traditionally regarded internal hydrogen-shift step. Finally, the implications of our results toward understanding the effect of acidity of zeolite on MTO activity are also discussed.

A cascaded model is proposed to establish the quantitative structure-activity relationship (QSAR) between the overall power conversionefficiency (PCE) and quantum chemical molecular descriptors of all-organic dye sensitizers. The cascaded model is a two-level network in which the outputs of the first level (JSC, VOC, and FF) are the inputs of the second level, and the ultimate end-point is the overall PCE of dye-sensitized solar cells (DSSCs). The model combines quantum chemical methods and machine learning methods, further including quantum chemical calculations, data division, feature selection, regression, and validation steps. To improve the efficiency of the model and reduce the redundancy and noise of the molecular descriptors, six feature selection methods (multiple linear regression, genetic algorithms, mean impact value, forward selection, backward elimination, and +n-m algorithm) are used with the support vector machine. The best established cascaded model predicts the PCE values of DSSCs with a MAE of 0.57 (%), which is about 10% of the mean value PCE (5.62%). The validation parameters according to the OECD principles are R(2) (0.75), Q(2) (0.77), and Qcv2 (0.76), which demonstrate the great goodness-of-fit, predictivity, and robustness of the model. Additionally, the applicability domain of the cascaded QSAR model is defined for further application. This study demonstrates that the established cascaded model is able to effectively predict the PCE for organic dye sensitizers with very low cost and relatively high accuracy, providing a useful tool for the design of dye sensitizers with high PCE.

Advances in material design and device engineering led to inverted organic solar cells (i-OSCs) with superior power conversionefficiencies (PCEs) compared to their ``conventional'' counterparts, in addition to the well-known better ambient stability. Here, we report an in-depth morphology study of the i-OSC active and cathode modifying layers, employing a model system with a well-established bulk-heterojunction, PTB7:PC71BM as the active layer and poly-[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) as the cathode surface modifying layer. We have also identified the role of a processing additive, 1,8-diiodooctane (DIO), used in the spin-casting of the active layer to increase PCE. Using various characterization techniques, we demonstrate that the high PCEs of i-OSCs are due to the diffusion of electron-accepting PC71BM into the PFN layer, resulting in improved electron transport. The diffusion occurs when residual solvent molecules in the spun-cast film act as a plasticizer. Addition of DIO to the casting solution results in more PC71BM diffusion and therefore more efficient electron transport. This work provides important insight and guidance to further enhancement of i-OSC performance by materials and interface engineering.Advances in material design and device engineering led to inverted organic solar cells (i-OSCs) with superior power conversionefficiencies (PCEs) compared to their ``conventional'' counterparts, in addition to the well-known better ambient stability. Here, we report an in-depth morphology study of the i-OSC active and cathode modifying layers, employing a model system with a well-established bulk-heterojunction, PTB7:PC71BM as the active layer and poly-[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) as the cathode surface modifying layer. We have also identified the role of a processing additive, 1,8-diiodooctane (DIO), used in the spin-casting of the active

In the paper, a novel three-layered chiral structure is proposed and investigated, which consists of a split-ring resonator sandwiched between two layers of sub-wavelength gratings. This designed structure can achieve simultaneously asymmetric transmission with an extremely broad bandwidth and high amplitude as well as multi-band 90° polarization rotator with very low dispersion. Numerical simulations adopted two kinds of softwares with different algorithms demonstrate that asymmetric parameter can reach a maximum of 0.99 and over than 0.8 from 4.6 to 16.8 GHz, which exhibit magnitude and bandwidth improvement over previous chiral metamaterials in microwave bands (S, C, X and Ku bands). Specifically, the reason of high amplitude is analyzed in detail based on the Fabry-perot like resonance. Subsequently, the highly efficient polarization conversion with very low dispersion between two orthogonal linearly polarized waves is also analyzed by the optical activity and ellipticity. Finally, the electric fields are also investigated and further demonstrate the correctness of the simulated and calculated results.

A novel bio-inspired Pt- and FTO-free integrated pure carbon counter electrode (CE) for dye-sensitized solar cells (DSSCs) has been designed and fabricated using a porous carbon sheet as a conducting substrate and ordered mesoporous carbon (OMC) as the catalytic layer. A rigid, crustose lichen-like, integrated carbon-carbon composite architecture with a catalytic layer rooted in a porous conducting substrate was formed by a process of polymer precursor spin coating, infiltration and pyrolysis. The integrated pure carbon CE shows very low series resistance (R(s)), owing to the high conductivity of the carbon sheet (sheet resistance of 488 mΩ □(-1)) and low charge-transfer resistance (R(ct)), due to the large specific surface area of the OMC layer that is accessible to the redox couple. The values of R(s) and R(ct) are much lower than those of a platinized fluorine-doped thin oxide glass (Pt/FTO) electrode. Cells with this CE show high solar-to-electricity conversionefficiencies (8.11%), comparable to that of Pt/FTO based devices (8.16%).

We report an effect of photoelectric conversionefficiency (PCE) by space layer doping in InAs/GaAs quantum dot solar cells (QDSC) and δ-doped QDSC grown by molecular beam epitaxy. The PCEs of QDSC and δ-doped QDSC without anti-reflection coating were 10.8% and 4.3%, respectively. The QDSC had about four electrons per QD, and its ideality factor was temperature-independent, which implies that recombination of electron-hole pairs is suppressed by strong potential barriers around charged dots. From the deep level transient spectroscopy measurements, four defect levels, including QD with the activation energy ranges from 0.08 eV to 0.50 eV below GaAs conduction band edge, appeared. Especially, the M1 defect (E{sub c}-0.14 eV) was newly formed in δ-doped QDSC and its density was higher than those of M3 (E{sub c}-0.35 eV) and M4 (E{sub c}-0.50 eV) levels in QDSC. These results suggest that the photo-carriers recombining at M1 defect might be responsible for the reduction of PCE in δ-doped QDSC.

Full Text Available The use of dye-sensitized solar cells (DSSCs is widespread owing to their high power conversionefficiency (PCE and low cost of manufacturing. We prepared multi-shaped Ag nanoparticles (NPs and introduced them into DSSCs to further enhance their PCE. The maximum absorption wavelength of the multi-shaped Ag NPs is 420 nm, including the shoulder with a full width at half maximum (FWHM of 121 nm. This is a broad absorption wavelength compared to spherical Ag NPs, which have a maximum absorption wavelength of 400 nm without the shoulder of 61 nm FWHM. Therefore, when multi-shaped Ag NPs with a broader plasmon-enhanced absorption were coated on a mesoporous TiO2 layer on a layer-by-layer structure in DSSCs, the PCE increased from 8.44% to 10.22%, equivalent to an improvement of 21.09% compared to DSSCs without a plasmonic layer. To confirm the plasmon-enhanced effect on the composite film structure in DSSCs, the PCE of DSSCs based on the composite film structure with multi-shaped Ag NPs increased from 8.58% to 10.34%, equivalent to an improvement of 20.51% compared to DSSCs without a plasmonic layer. This concept can be applied to perovskite solar cells, hybrid solar cells, and other solar cells devices.

We report on Y3Al5O12: Ce(3+) ceramic phosphor plate (CPP) using nano phosphor for high power laser diode (LD) application for white light in automotive lighting. The prepared CPP shows improved luminous properties as a function of Ce(3+) concentration. The luminous properties of the Y3Al5O12: Ce(3+) CPP nano phosphor are improved when compared to the Y3Al5O12: Ce(3+) CPP with bulk phosphor, and hence, the luminous emittance, luminous flux, and conversionefficiency are improved. The Y3Al5O12: Ce(3+) CPP with an optimal Ce(3+) content of 0.5 mol % shows 2733 lm/mm(2) value under high power blue radiant flux density of 19.1 W/mm(2). The results indicate that Y3Al5O12: Ce(3+) CPP using nano phosphor can serve as a potential material for solid-state laser lighting in automotive applications.

Metasurfaces made of subwavelength resonators can modify the wave front of light within the thickness much less than free space wavelength, showing great promises in integrated optics. In this paper, we theoretically show that electric and magnetic resonances supported simultaneously by a subwavelength nanowire with high refractive-index can be utilized to design metasurfaces with near-unity transmittance. Taking silicon nanowire for instance, we design numerically a near-infrared quarter-waveplate with high transmittance using a subwavelength nanowire array. The operation bandwidth of the waveplate is 0.14 μm around the center wavelength of 1.71 μm. The waveplate can convert a 45° linearly polarized incident light to circularly polarized light with conversionefficiency ranging from 94% to 98% over the operation band. The performance of quarter waveplate can in principle be tuned and improved through optimizing the parameters of nanowire arrays. Its compatibility to microelectronic technologies opens up a distinct possibility to integrate nanophotonics into the current silicon-based electronic devices.

The conversionefficiency (ε(c)) of absorbed radiation into biomass (MJ of dry matter per MJ of absorbed photosynthetically active radiation) is a component of yield potential that has been estimated at less than half the theoretical maximum. Various strategies have been proposed to improve ε(c), but a statistical analysis to establish baseline ε(c) levels across different crop functional types is lacking. Data from 164 published ε(c) studies conducted in relatively unstressed growth conditions were used to determine the means, greatest contributors to variation, and genetic trends in ε(c )across important food and biofuel crop species. ε(c) was greatest in biofuel crops (0.049-0.066), followed by C4 food crops (0.046-0.049), C3 nonlegumes (0.036-0.041), and finally C3 legumes (0.028-0.035). Despite confining our analysis to relatively unstressed growth conditions, total incident solar radiation and average growing season temperature most often accounted for the largest portion of ε(c) variability. Genetic improvements in ε(c), when present, were less than 0.7% per year, revealing the unrealized potential of improving ε(c) as a promising contributing strategy to meet projected future agricultural demand.

Ag nanowires (AgNWs) were employed in mesoporous TiO2 dye-sensitized solar cells (DSSCs) to enhance the photoelectric conversionefficiency (PCE). The possible reasons for PCE improvement, i.e., improvement in electron transport and light harvesting due to light scattering and plasmonic resonance effect of AgNWs are investigated. Electrochemical impedance spectra (EIS) study proved that addition of AgNWs can enhance the conductivity of TiO2 thin film photoanode, which is an important reason for the increase of photocurrent. Furthermore, through the comparison experiments as well as the UV-Vis absorption and IPCE characterization, contributions of the light scattering and plasmonic resonance effect to the enhancement of light harvest, and thus PCE of the DSSCs were demonstrated. It was found that fast electron transport of AgNWs played more important role for the PCE improvement than the light harvest enhancement due to light scattering and plasmonic effect. Based on these investigations, the AgNWs modified TiO2 thin film DSSCs were optimized. After integrating AgNWs into the photoanode, the photocurrent increased significantly and PCE increased -50% comparing with the pure TiO2-based DSSCs.

High x-ray conversionefficiency (XRCE) L-shell Ag sources are being developed for High Energy Density experiments. The targets are nominally 4 mm in diameter, 4 mm tall cylinders of free standing Ag metal foam with densities of 10 - 30 mg/cm3 and made by a new technique of freeze drying an aqueous suspension of Ag nano wires. 192 laser beams from NIF are used to heat the targets with 150 TW of power in a 4 ns square in time pulse depositing 600 kJ into the target. XRCEs from these targets have been measured by using the Dante diode spectrometer to be 7% which is much less than the predictions from simulations. The nano wires at nominal solid density might not be homogenized sufficiently by the laser heating pulse which could limit the XRCE. To increase the XRCE, we plan to use a laser prepulse of 1 kJ to preheat the nano wires in the target before the main laser heating pulse. The results of these experiments will be discussed. This work was performed under the auspices of the US Department of Energy by University of California Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

Two-component self-assembly supramolecular coordination complexes with particular photo-physical property, wherein unique donors are combined with a single metal acceptor, can be utilized for many applications including in photo-devices. In this communication, we described the synthesis and characterization of two-component self-assembly supramolecular coordination complexes (SCCs) bearing triazine and porphyrin faces with promising light-harvesting properties. These complexes were obtained from the self-assembly of a 90° Pt(II) acceptor with 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPyT) or 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (TPyP). The greatly improved conversionefficiencies of the dye-sensitized TiO2 solar cells were 6.79 and 6.08 respectively, while these SCCs were introduced into the TiO2 nanoparticle film photoanodes. In addition, the open circuit voltage (Voc) of dye-sensitized solar cells was also increased to 0.769 and 0.768 V, which could be ascribed to the inhibited interfacial charge recombination due to the addition of SCCs.

Optically resonant donor polymers can exploit a wider range of the solar spectrum effectively without a complicated tandem design in an organic solar cell. Ultrafast Förster resonance energy transfer (FRET) in a polymer-polymer system that significantly improves the power conversionefficiency in bulk heterojunction polymer solar cells from 6.8% to 8.9% is demonstrated, thus paving the way to achieving 15% efficient solar cells.

To control of hydrocarbon content in waste pyrolysis-gasification and reforming processes, the use of a hydrogenation catalyst was examined in a test system with a model gas. To reduce the concentration of benzene in the reforming gas, benzene was hydrogenated with a nickel catalyst. The catalyst is usually used to convert gas-phase unsaturated hydrocarbons to saturated hydrocarbons, and the benzene was converted to cyclohexane at a temperature range of about 130 to 180 degrees C in the presence of steam. However, the conversion to methane occurred at about 250 to 300 degrees C. Methane seems to be a useful conversion compound because it does not cohere as a light tar. Sometimes the reforming gas needs to be cooled for use as generator fuel. In this case, it is possible to avoid the tar cohesion if the benzene in the gas is converted to methane at about 300 degrees C after the reforming. Reduction of the efficiency of conversion to methane was not observed over a 60h reaction period. The lower hydrocarbons (ethylene, ethane, and propylene) were also converted to methane at about 300 degrees C. Conversion of benzene was also possible when other hydrocarbons were present at high concentrations.

DFT investigations on beryllium-doped boron nitride meshes or sheets (BNs) predict the existence of a very reactive kind of novel material capable of spontaneously reducing the first hydrogenation step in the CO2 conversion mechanism. This impressive behaviour appears as a result of the very deep π-hole generated by the beryllium moieties, and also determines its selectivity towards the production of CH4.

This report describes a proposed thermochemical process for converting biomass into liquid transportation fuels via fast pyrolysis followed by hydroprocessing of the condensed pyrolysis oil. As such, the analysis does not reflect the current state of commercially-available technology but includes advancements that are likely, and targeted to be achieved by 2017. The purpose of this study is to quantify the economic impact of individual conversion targets to allow a focused effort towards achieving cost reductions.